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REACTIVE POWER MANAGEMENT

Editorial Board

Advisor:

Dr. R. Nagaraja

Editor:

M.M. Babu Narayanan

Members:

Faraz Zafar Khan

Poornima T.R.

Amit Nigam

Maheedhar Patnala

Rajesh Kanchan

Thimmappa N.

Inside This Issue

From MD's Desk……………………………………………........…………………..…………......….…. 2

An Insight into Reac�ve Power……………………………………………………. R. Nagaraja 4

Developments in Reac�ve Power Management : Building up Dynamic Reservesin the Indian Grid…………………………………........................................ Lalit Tejwani 10

Reac�ve Power Management – An overview……………….…….Shekhar M Kelapure 14

Reac�ve Power Market in select Countries………..Rakesha H.S and K. Balaraman 16

Consultancy Services Rendered:

Reac�ve Power Management & Harmonic Analysis for Oil & Gas Plant

in Qatar……………………………………………………………………………………………… 18

IT Drives Power Sector Efficiency………………………………………………………. 19

Events & Achievements……………………………………………………………………………………. 21

Our Exper�se in Training…………………………………………………………………………………… 22

HR @ PRDC……………………………………………………………………………………………………….. 23

Indian Power Sector Highlights…………………………………………………………………………. 24

About the Authors…………………………………………………………………………………………….. 25

R.N.I No. KARENG/2013/51589

July - December, 2014July - December, 2014July - December, 2014Quarterly NewsletterQuarterly NewsletterQuarterly Newsletter

POWER RESEARCH AND DEVELOPMENT CONSULTANTS

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Power Research and Development Consultants

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Dear Friends, During the past 10 years, I have been often visiting Gurgaon in Haryana. One thing that I have noticed in all these visits is that the infrastructure development activities have not stopped from day one till date. Initially, it started with the development of roads, office spaces and the township. Then the Metro Rail construction started, followed by Mono Rail activities. Now, few Flyover constructions are also under progress. The commuters and local residents are always exposed to the vagaries of construction and the hardship of having to drive through these roads not forgetting the difficulties for pedestrians. Needless to state here, the story is the same with most of the cities in India. The sad

part of this development is, we as citizens are not

enjoying the benefits of such infrastructure projects since one or the other construction activities keep happening. The main reasons are that we never think big and always start constructing to correct the past, rather than building the kind of infrastructure that would take care of the future as well. The end result is continued & never ending hardships to one and all. You may wonder why as a power system engineer, I am talking about the infrastructure projects related to civil engineering domain. A similar situation exists even in the power system field. There is one quantity called “Reactive Power”, which is to be understood in the right perspective. We keep on building new transmission corridors only to handle the active power transfer, ending up always, not being able to optimally utilize these facilities as built. One of the major reasons is the inability to push more active power in the given corridor due to frequent line over loading and the high and low voltage related issues that are

attributed to lack of reactive power management. In this newsletter, we are addressing “Reactive Power” issues and management of the same. Ideal power system is one wherein frequency and voltage are constant at every supply point, system is free from harmonics and power factor is unity. Reactive power control is required to improve the quality of power supply in ac power systems and to have better utilization of existing equipment resulting in the deferment of new investment for equipment purchases. Reactive power in the power system arises due to inductance and capacitance in the electrical circuit. Inductance stores the energy in the magnetic field when current is increased and delivers it back to circuit when the current is decreased. Capacitance stores the energy in the static/dielectric field, also known as insulating medium. Reactive power consumed by the loads is fairly easy to understand, but the reactive power generated or consumed within the network is difficult to comprehend and

From MD’s Desk

Power Research and Development Consultants Newsletter

is of major concern. In a well-planned system, the reactive power management addresses the control of generator voltages, transformer tap settings, fixed reactive compensation, switchable shunt capacitor and reactor banks, power electronics based shunt & series compensators plus allocation of new shunt capacitor and reactor banks in a manner that best achieves a reduction in system losses and/or voltage control. Reactive power control will ensure system security and also lead to economic operation of the power system. In the past, most of the grid collapses were attributed to angular instability problem, i.e., machines going out of step following a disturbance. However, with the faster fault clearing times, special protection schemes in place and sophisticated control systems, angular instability problems related system disturbances have come down. The phenomenon increasingly being observed in the recent past is the voltage instability related issues in the interconnected system.

Voltage instability problem occurs when the transmission lines are heavily loaded with inadequate reactive power support in the system. Reactive power control and management has suffered due to lack of knowledge and understanding by the industry and also the absence of economic incentives for supporting the system with reactive power sources, both in terms of injection and drawl. Through articles in this Newsletter, we have attempted to highlight the importance of reactive power management in power systems namely: •Reactive power control and management is an important aspect in the operation and control of power system •A proper mix of excitation system control, transformer tap control and switchable Var source control will achieve the objective of reactive power control. •Advances in technology in the SCADA & EMS in addition to deployment of FACTS devices will enable better reactive power control. I thank all those who have

contributed to this Newsletter through their technical articles. My special thanks are to Shri Lalit Tejwani from M/s RXPE who has contributed the article covering important aspects of reactive power management in the Indian context. I also thank the engineers from PRDC who have contributed the technical articles in this Newsletter. Special thanks to the “PRDC Newsletter” committee. I wish all the readers, their family and friends happy and prosperous new year 2015.

Dr. R. Nagaraja Managing Director


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I. Introduction Power is the product of voltage and current. Power is an energy related quantity flowing in the electrical network instantaneously. When the voltage and current are not in phase, their product results in active and reactive powers. Reactive power refers to the circulating power in the electric network, which does no useful work and results from energy storage elements viz., inductor and capacitor. While planning, designing and operating the electric infrastructure, many system planners neglect the reactive power component of the power resulting in the systems inadequately designed, not meeting the power quality standards. The way there is close correlation between the active power and the system frequency, there exists a close correlation between the reactive power and voltage. Most of the blackouts in the grid in the recent past have been attributed to voltage drops related to reactive power. Proper reactive power management and voltage control will mitigate the risks of voltage collapse related blackout in the systems. In this article, the reactive power and voltage related issues specific to various power system components are discussed. II. Power System Elements and Reactive Power Generators and synchronous condensers operated with a leading angle, shunt reactors, line and transformer inductances, static reactive power compensators operated in the inductive mode and inductive loads are the sinks of the reactive power. Generators and synchronous condensers operated with a lagging angle, shunt capacitors, capacitance of lines and cables, static reactive power compensators operated

in the capacitive mode are the sources of the reactive power. In this section, the behaviour of the reactive power with reference to specific power system components is discussed.

A. Transformer Transformer is the integral part of any electrical system. From the generating station to the end consumer, there are about five to six transformation levels in most of the electrical systems, based on the technical and economic considerations. Specific to Indian context, in a State like Karnataka, there exists voltage transformation from generating bus voltage to 400 kV termed as generating transformers (GT), 400kV to 765 kV, 400 kV to 220 kV, 220 kV to 110 kV at transmission level, 110 kV to 33 kV at sub-transmission level, 33 kV to 11 kV and 11 kV to 415 V at distribution system level. The impedance of the transformer is predominantly inductive in nature and the leakage impedance is measured from the short circuit test. The per unit impedance of the power transformer on its own rating conveys the following: • The reactive power consumption • The voltage drop • The fault level at the secondary of the transformer, when the fault level at the primary side of the transformer is infinite (negligible source impedance).

For the power and generator transformers, the percentage impedance on its own rating is in the range 8-14%. A 500 MVA transformer, having 12% impedance, when fully loaded consumes about 60 Mvar. A 500 MW power plant with 625 MVA GT having 14% impedance, when loaded 500 MW, consumes about 56 Mvar. Even if the power plant person argues with the load dispatch personnel that the power plant is generating 56 Mvar, at the HT bus of the power plant, no Mvar is being injected to the system. Reactive power loss in the transformer varies as the square of the loading and a 100 MVA, 10% impedance, fully loaded transformer consumes 10 Mvar, while at 50% loading, it consumes 2.5 Mvar. Consider a utility catering to a load of about 10,000 MW at 11 kV through 5 stages of transformation. Consider the installed capacity of transformers at each level to be around 15000 MVA. Considering the 10% transformer impedance in an average at all levels, the reactive power requirement at the transformation itself will be more than 3333 Mvar even at unity load power factor. Hence the power engineers need to understand that it is not just the load power factor one need to compensate, the reactive power consumption at each transformation level needs to be compensated.

Technical Article An Insight into Reactive Power

R. Nagaraja

Figure 1: Voltage and Current Phasors for Transformer Loading


Voltage drop in the transformer depends on the load power factor. Consider a 100 MVA transformer, 10% impedance, which implies reactance is close to 10%, as the resistance is negligible. Figure 1 shows the phasor diagram of the voltage and current at different load power factor. From the phasor diagram, it is observed that if the transformer is fully loaded at unity power factor, the voltage drop is negligible. If the transformer is fully loaded at zero power factor, the voltage drop is 10%. It can be concluded that the voltage drop in the transformer is mainly due to the reactive power flow in the transformer and hence always better to compensate the load power factor to minimize the reactive power flow through the transformer. In few utilities, more than two transformers are connected in parallel to improve the power supply reliability. However, the secondary fault level will increase in this system configuration. In order to reduce the fault level, the transformer with higher percentage impedance is opted. It should be noted that higher impedance consideration to limit the fault level increases the reactive power loss in the transformer and also causes the voltage regulation problem and frequent tap operation for the varying lagging power factor loading conditions. B. AC Transmission line AC transmission line has distributed resistance and inductive reactance connected in series and distributed capacitive susceptance connected to ground. Transmission lines acts as both source and sink of reactive power, depending on the line loading. Table 1 shows the transmission line parameters of typical configuration. Table also shows the pu impedance values expressed on the MVA rating of the line. From the table, following inferences and conclusions are drawn.

• A 400 kV, 100 km long line generates about 60 Mvar when idle charged and for 220 kV line it is around 14 Mvar, for 110 kV line, it is 3.5 Mvar and for 66 kV line, it is 1 Mvar. This implies that for the overhead lines below 66 kV, as the line lengths are short, line charging susceptance can be neglected. • Line reactors are required at 400 kV to mitigate the over voltage at the receiving end, as line acts as a huge capacitor during idle charged condition and receiving end voltage will be raised

due to Ferranti effect. Typical values of line reactors used in Indian transmission system at 400 kV are 50 Mvar, 63 Mvar and 80 Mvar at 420 kV voltage rating. For a 300 kV long line, if 63 Mvar reactors are used both at sending end and at receiving end, at 400 kV the effective compensation works out to 114 Mvar. The shunt compensation factor accounts to 63% in this case. • How much of the line inductive reactance is negated by the capacitive reactance connected in series in the line

Table 1: Transmission Line Parameters

Voltage kV 400 220 110 66

Line type Twin

Moose Zebra Panther Wolf

R ohm/km 0.029 0.07 0.162 0.257

X ohm/km 0.308 0.398 0.386 0.432

B mho/km 3.76E-06 2.91E-06 2.93E-06 2.66E-06

Line loading and Base MVA 500 200 80 25

Typical line length km 300 150 50 25

R pu for entire line length 0.0271875 0.043388 0.053554 0.036874

X pu for entire line length 0.28875 0.246694 0.127603 0.061983

B pu for entire line length 3.61E-01 1.06E-01 2.21E-02 1.16E-02 Line charging Mvar - 100 km

at rated voltage 60.16 14.10 3.54 1.16 Line charging Mvar entire line

length at rated voltage 180.48 21.16 1.77 0.29 Reactive power loss in Mvar

at 100% loading at rated voltage 144.375 49.33884 10.20826 1.549587

Figure 2: Receiving end voltage raises, when sending voltage is maintained

behind the source impedance


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determines the series compensation factor. If the 400 kV, 300 km line is 50% series compensated, it can be concluded that reactive power loss at 100% loading will come down to 72 Mvar from 144 Mvar. • At times, the shunt reactive power requirement is decided considering only the transmission line of interest and by assuming one per unit voltage at the sending end and determining the receiving end voltage to control it to its acceptable limit. However, it should be noted that the line charging capacitive current has to flow through the generating transformer (GT), having about 14% impedance on its own rating. As the generator terminal voltage is maintained at 1 pu, there will be further raise in the voltage at the receiving end (Figure 2). This is of major concern in many utilities when adequate system studies are not carried out to find the shunt reactor requirement in the system. From figure 2, it is seen that there is almost 4% difference in the receiving end voltage, when the voltage at the generator terminal is maintained at 1 pu. • Inductive current flowing in an inductive circuit from the sending end to receiving end causes the fall in the voltage at the receiving end. Capacitive current flowing in an inductive circuit from receiving end to sending end causes the raise in the voltage at the receiving end. Capacitive current flowing in a capacitive circuit from receiving end to sending end causes the fall in the voltage at the receiving end. Hence the midpoint series compensation or the series compensation at the sending end reduces the requirement of the shunt inductive compensation (Figure 3). From figure 3, it can be observed that 50% series compensation at the sending end has the same effect of 63 Mvar shunt inductor at the receiving end, in terms of voltage control. However, net reactive power generation in the line is not controlled in case of series compensation. Inductive current flowing in a capacitive circuit from sending end

to receiving end causes rise in the voltage. During the system fault, as the fault current is predominantly inductive in nature, series capacitor should have adequate voltage protection through the surge arrestor connected across the capacitor to bypass the capacitor.

• For the typical line lengths considered, line also consumes the reactive power due to the I2x depending on the line loading. For 400 kV, 300 km long line, when the line is fully loaded with line reactors on either ends, it is a sink of reactive power. It should be noted that for higher loading, as the voltage falls, the current increases to deliver required power and hence, reactive power consumption in the line increases while the Mvar generation from the line charging susceptance comes down. • X pu on the line MVA rating for the entire line length indicates that when the reactive power flows in the line, there is considerable voltage drop, which implies, it is better to compensate the reactive power and minimize the reactive power drawl on the line. • Assume that a 220 kV, 100 km long double circuit line connects an IPP (independent power producer) power plant to the transmission utility system and the energy meter is placed at the receiving end, i.e. at utility substation. The power plant may be drawing the

auxiliary power of about 10 MW at 0.9 pf at certain instant. The reactive power injection to the grid at the interface point will be around 23 Mvar (28 Mvar reactive power generation by the line as per table 1). The recorded power factor at the meter point will be around 0.4

lead. The poor power factor is due to the line charging Mvar of the 100 km long double circuit line and it will be improper to charge the IPP for poor power factor. C. Shunt Capacitor and Inductor Shunt capacitor is the source of reactive power and shunt inductor is the sink of reactive power. The reactive power injection or drawl depends on the square of the system voltage. A 50 Mvar shunt inductor rated at 420 kV draws only 45 Mvar at 400 kV operating voltage. A 10 Mvar capacitor rated at 72 kV when connected to 66 kV system and operated at 66 kV injects only 8.4 Mvar. In many of the utilities, capacitive compensation is provided at 132 kV, 110 kV, 66 kV, 33 kV and 11 kV. During the peak load condition, when the secondary voltage of the transformer is poor, by proper operation of the transformer tap and maintaining the adequate voltage, the effective utilization of the capacitor bank can be seen. Some of the utilities have the

NOTE : Display notation similar to figure 2

Figure 3: Comparison between Series Compensation and Shunt Compensation


feeling that the radially connected substations need not be monitored through SCADA. The life of the capacitor bank can be enhanced by monitoring the system voltage and disconnecting the capacitor banks during off peak loading conditions. Shunt inductive reactors play an important role in curtailing the system voltage during the light load condition. Load flow studies during light load conditions should be conducted to determine the adequate shunt inductive compensation in the system to mitigate the over voltage. Bus reactors (Figure 4) when deployed will mitigate the steady state over voltage and line reactors will mitigate both steady state over voltage and also switching over voltage. Continuous over voltage at 400 kV in the Indian system may be due to inadequacy of the shunt inductive reactors in the system. Proper deployment, monitoring, operation and maintenance of the shunt inductive reactors should be practiced to curtail the prevailing over voltage in the 400 kV system in India.

Life of the shunt capacitor can be enhanced by adopting best operational practices and maintenance procedures. A capacitor with low value of series reactor injects the capacitive harmonic current into the system when subjected to specific harmonic voltage till the resonant frequency. Deployment of the capacitor banks in the system having harmonic power quality issues without adequate harmonic measurement and analysis may cause the frequent failure of the capacitor banks. D. Generator Generators are both source and sink of

reactive power. A generator is said to be operating in the lagging power factor, when it injects the reactive power at its terminal and over excited and is said to be operating in the leading power factor, when it absorbs the reactive power at its terminal and is under excited. A generator reactive power should be within the capability limits of the machine, as shown in figure 5. At low active power, the generator reactive power injection to the grid is limited by the rotor heating limit. When the machine starts generating more and more active power, the reactive power generation is limited by the stator heating limit. The reactive power absorption is limited by the stability limit. Most of the grid codes stipulate that the

thermal and nuclear machines should not be operated in the leading power factor, even though the capability exists. Power plant personnel are also scared to operate the machine in the leading power factor. Figure 6 shows the generator voltage and current phasors corresponding to lagging, unity and leading power factor drawn for both hydro and thermal machines. The quadrature axis reactance (Xq) of hydro machine is generally in the range 0.8 to 1 pu and the same for the thermal machine is in the range 1.6 to 2 pu. Considering the Xq value of 1 pu and 2 pu respectively for hydro and thermal

machines, IXq drop will be 1 pu and 2 pu respectively, for rated load current of 1 pu. It is clearly observed that for the thermal machine, the rotor angle is higher compared to hydro machine and the rotor angle moves towards 90 degree, the steady state stability limit when the thermal machine is operated in the leading power factor.

In the power flow studies, the maximum limit of the reactive power is generally scheduled as 50% of the active power schedule, indicating a 0.90 operating power factor and the reactive power minimum is set as zero or -10% of the active power schedule for the thermal machine and for hydro machine, reactive power minimum can be set as -25% of the active power schedule. Most of the generator transformer tap control is of off load type and hence the tap is set at +5% to push the reactive power to the grid and further injection of the reactive power is controlled by the excitation system voltage (AVR) control.

Figure 4: Bus and Line Reactors

Figure 5: Generator Capability Curve

Figure 6: Generator Voltage and Current Phasor


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E. Load Most of the loads are inductive in nature and the reactive power drawn is a function of voltage. Table 2 gives the typical power factor of different equipment. Induction motor running at no load or low load draws considerably high reactive power. When the motor is operated at reduced voltage, the reactive power draw increases, as slip increases or speed comes down. Agricultural pump load being predominant in many of the States in India, low voltage in rural India increases the reactive power drawl by the pump sets, further lowering the voltage, resulting in higher system losses and burning out of pump sets. Electric arc furnaces, induction furnaces, submerged arc furnaces have relatively low power factor, and require capacitive reactive power compensation. Compensation at the consumer load point is decided based on the technical aspects like voltage improvement, relieving the equipment loading, power factor improvement as per the grid code, loss reduction etc. and the proposal is strengthened by the economic feasibility study.

F. HVDC Terminal HVDC systems using line-commutated converter consumes reactive power, whether it is rectifier station or it is inverter station. Hence, HVDC terminal is always a sink of reactive power. The reactive power absorbed is at least 0.5 Mvar/MW under ideal conditions and can be higher than this when the converter is operating at higher than

usual firing or extinction angle, or reduced DC voltage. The reactive power support is given by a set of capacitor banks, which also act as harmonic filters to filter the harmonic current generated by the converter from enetering the ac system. The shunt capacitors are usually connected directly to the grid voltage but in some cases may be connected to a lower voltage via a tertiary winding on the converter transformer. In case of voltage-source converters, as they can either produce or consume reactive power on demand; usually no separate shunt capacitors are needed. III. Reactive power Management Having understood the reactive power behaviour with reference to various power system components, it is important to look into the management of the reactive power. Reactive power management is defined as the control of generator voltages, variable transformer tap settings, compensation, switchable shunt capacitor and reactor banks plus allocation of new shunt capacitor and reactor banks in a manner that best achieves a reduction in system losses and/or voltage control. Reactive power management can further be classified into reactive power planning, system operations planning and reactive power dispatch and control. Reactive Power Planning: Reactive power planning is concerned with the installation or removal of reactive power equipment in a power system. System conditions for the future system are studied and reactive power planning is done in advance. Reactive power planning becomes more crucial, when the system load increases and more and more EHV lines are added to the system. Objective of reactive power planning is to minimize the cost of necessary reactive power equipment to enable the power system to operate in an acceptable manner in the event of any credible contingencies occurring in the system. Reactive power planning

problem involves determining optimal installation of reactive power support both in terms of quantum and location in the system, which satisfies every contingency. System Operations Planning: System operations planning is concerned with the improvement in operating practices utilizing existing reactive power equipment. This planning is performed for system conditions anticipated to occur a few days to a year into the future. Reactive Power Dispatch & Control: Reactive power dispatch and control determines the actual equipment operations. Reactive power analysis is performed seconds to hours prior to its implementation. Reactive power optimization program running in the load dispatch center helps in the reactive power dispatch and control. Voltage instability study module of the EMS tool determines the voltage collapse proximity indicator at the load buses and suggestive measures can be taken up. IV. Reactive Power Control – FACTS Devices Flexible AC Transmission Systems (FACTS) are the name given to the application of power electronics devices to control the power flows and other quantities in power systems. As per IEEE the definitions are – FACTS: AC transmission systems incorporating the power electronic-based and other static controllers to enhance controllability and increase power transfer capability. FACTS Controllers: A power electronic based system & other static equipment that provide control of one or more AC transmission parameters. Flexibility of electric power transmission: The ability to

Table 2: Typical power factor of Equipment

Equipment Power factor Air Compressor & Pumps

0.75 – 0.80

Arc Welding 0.40 - 0.60 Resistance Welding 0.45 - 0.65 Arc Furnaces 0.70 - 0.85 Induction Furnaces 0.80 - 0.90


accommodate changes in the transmission system or operating conditions while maintaining sufficient steady state & transient margins. Limitations in the AC transmission system are steady state, dynamic and transient stability limits, voltage stability problem and sub-synchronous resonance problems associated with series compensated lines and thermal power plants. Further, AC transmission systems have inherent problems of loop flows, voltage limits being violated due to reactive power flow and over loading besides inability to load the line to the thermal limit due to voltage and stability problems. Benefits of FACTS Technology is to increase the power transfer capability of transmission networks and to provide direct control of power flow over designated transmission routes. Further FACTS technology offers the opportunities like - • Use of control of the power flow to follow a contract, meet the utilities’ own needs, ensure optimum power flow • Increase the loading capability of lines to their thermal capabilities, including short-term and seasonal.

• Increase the system security and damping of electromechanical oscillations. • Provide secure tie line connections to neighboring utilities and regions thereby decreasing overall generation reserve requirements on both sides. • Damping of power oscillation, • Preventing cascading outages by limiting the impact of faults and equipment failures. • Provide greater flexibility in siting new generation. • Reduce reactive power flows, thus allowing the lines to carry more active power. • Increase utilization of lowest cost generation. Even though the detailed discussion on FACTS is beyond the scope of this article, it is concluded that judicious deployment of the FACTS devices in the AC system following the thorough system studies and investigation will

benefit the utilities. Figure 7 shows that with 50% series compensation, 129 Mvar reactive power injection through SVC at bus 12, the line loading can be almost doubled from that of the un-compensated line. It is also to be noted that the angular separation is around 20 degree and is remaining the same in both the cases. It is concluded that the linear asset creation always being the challenge, existing transmission transfer capability can be enhanced by FACTS devices. While the investment to build the 300 km long 400 kV line costs about Rs. 300 Cr, the combined cost of SVC and the TCSC will be much lesser and ROW issues will not be present.

V. Conclusions In this article, the reactive power behaviour specific to different power system elements are discussed. The reactive power management and control is essential at the distribution, transmission and generation levels to ensure the quality of power supply and to have system security. Best operated power system is one, wherein the reactive power flow through its elements is to the minimum and voltages are maintained close to unity, which can be achieved by economically monitoring and controlling the reactive power at various locations.

NOTE : Display notation similar to figure 2

Figure 7: Line loading with and without compensation


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Synopsis India’s transmission and distribution system is continuously evolving due to grid integration, deregulation, privatization, distributed power plants with higher voltage levels, having a greater exchange between interconnected systems and transport to large load centres over long transmission lines. To ensure safe and reliable operation, electrical grids are designed with redundancy, protection mechanisms and with sophisticated monitoring and control systems. However in the absence of proper emergency control and dynamic compensation capability, system faults may lead to voltage instability causing cascading failures. To prevent network wide cascading failure like we saw in July’12, India’s electricity regulatory authority has strategized building up of dynamic reactive power reserves in the Indian transmission grid. This entails installing dynamic reactive power compensation systems at strategic locations across the country. The article gives an overview of selection of suitable reactive power compensation system in relation to the expectations of India’s transmission network. I. Indian Electricity Regulatory Authorities’ Emphasis on Dynamic Reserves The electricity sector in India had an installed capacity of 254.049 GW as of end September 2014. India became the world's third largest producer of electricity in the year 2013 with 4.8% global share in electricity generation surpassing Japan and Russia. Captive power plants have an additional 39.375 GW capacity. Non-renewable Power Plants constitute 87.55% of the installed capacity, and Renewable Power Plants constitute the remaining 12.45% of total

installed Capacity[1]. When transmission lines operate beyond surge impedance loading, reactive power is consumed by the line and voltage drops. High active power (MW) flow, coupled with reactive power (MVAR) loss/flow in the line, leads to low voltage and high current. This may cause load encroachment in the relays, i.e. normal load may be seen as fault leading to tripping of lines in real-time operation. Northern and eastern India endured the world’s largest power failure in the month of July 2012, with a blackout that affected almost 60% of India’s, and 10% of world population.The report on the grid disturbance on 30th and 31st July, 2012 submitted in compliance to Central Electricity Regulatory Commission (CERC) order in petition no. 167/suo-motu/2012 dated 8th August 2012[3] stated that on both the occasions, i.e. on 30th and 31st July 2012, there was high loading on West-North corridor, especially 400 kV Bina-Gwalior, which was carrying more than Surge Impedance Loading (SIL) rating and this

led to low voltages at the Gwalior end in the event of high line loading. The committee, inter alia, recommended installation of adequate static and dynamic reactive power compensators to provide voltage support under steady state and dynamic conditions. Referring to Central Electricity Authority’s (CEA) document [3], static reactive power compensators was agreed at additional 13 nos. of 400kV transmission substations. It was also agreed that the choice of reactive power management technology would be evaluated with help of external consultant and industry interaction. II. Principle of Reactive Power Compensation Electrical characteristics of the network contribute to the phase and magnitude difference in current and voltage, thus causing reactive power (MVAR) flow in the electrical system. Reactive Power Compensation is defined as the management of reactive power to improve the performance of AC power systems both at the utility side and at the user side.

Figure 1: Reactive Power Compensation Development

Developments in Reactive Power Management: Building up Dynamic Reserves in the Indian Grid

Lalit Tejwani


Either series or shunt VAR compensation is used to modify the natural electrical characteristics of ac power systems. Shunt compensation changes the equivalent impedance of the load thus controlling the reactive power flowing through the system and improving the performance of the overall ac power system. Shunt capacitor and reactor / inductor banks connected at strategic points in the network provide the required VAR support to the electrical system. To control the amount of VAR compensation, these branches may be fixed or mechanically switched capacitors or inductors. (See Figure 1) In recent years, Static VAR Compensators (SVC) employing thyristor switched capacitors and thyristor controlled inductors provide faster, step-less VAR compensation. An SVC comprises one or more banks of shunt capacitors and / or inductors, and harmonic filters. If the power system's reactive load is capacitive (leading), the SVC will switch in its inductors to consume VARs from the system, preventing system over-voltage. Under inductive (lagging) and heavy load conditions, the capacitor banks are automatically switched in, thus providing support to system voltage. This increases maximum transmittable power, regulates the voltage profile, and prevents voltage instability. III. Next-generation Step–less VAR Compensator – STATCOM Static Synchronous Compensator (STATCOM) has earned its name as it does not have any rotating or moving parts like the synchronous condensers, and yet offers a fast and step-less VAR compensation. It is based on VSC technology, which uses low-voltage cells in series to realize a high voltage output. This is the same technology being used for state-of-the-art VSC-HVDC systems. By controlling the output voltage to be either higher or lower, STATCOM will

draw a capacitive or inductive current from the system. Even without control action, STATCOM has a natural tendency to compensate for changes in system voltage, but its low stored energy means it can do this much more rapidly than a synchronous condenser. Also unlike a constant impedance device like a capacitor or inductor whose output current will decrease with voltage, STATCOM can continue to

generate its maximum output current even at low system voltages as it is not dependent on passive reactive components. (Figure 4) STATCOM has superior performance in response speed, stability of voltage level, reducing system loss, increasing transmission capacity and improving transient voltage limit, reducing harmonics and decreasing equipment

Figure 2: Typical SVC installation

(Courtesy: Rongxin Power Electronics Ltd)

Figure 3: Model of Europe’s largest 750 MVAR SVC



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footprint. The main features and advantages of STATCOM may be summarized as follows: • It has a faster response time & stronger mitigation ability for voltage fluctuation • Smaller footprint compared to SVC (1/3 in some cases) • Being an indoor solution, it has better protection, and longer life expectancy compared to traditional SVC • Filters not required as STATCOM generates negligible harmonics and absence of capacitor/inductor switching • STATCOM solution is modular, hence redundancy with hot by-pass and future system expansions are possible with minimum engineering costs in comparison to traditional SVC systems • STATCOM can be realized in containerized solution to make it even more compact and flexible. Moreover it can easily be re-located and rapidly deployed in areas needing immediate VAR correction. • STATCOM at reduced voltage can still inject maximum current, whereas SVC current capability reduces in proportion to voltage. As demonstrated in Figure 6, compared to SVC, STATCOM has a wider operating range, can offer increased transient rating in both the inductive and capacitive operating regions. Full

output current of STATCOM is also available down to low system voltages, typically as low as 0.30 p.u.

IV. Dynamic Compensation Plans for India’s Transmission Grid In order to finalize the technology, rating / sizing of dynamic compensation for Indian grid condition, Power Grid Corporation of India Ltd. (POWERGRID) interacted with various manufactures,

utilities. POWERGRID has appointed an expert in the field of HVDC, FACTS, Power System as consultant and had detailed deliberations on the technological and rating aspects of dynamic compensation requirements. STATCOM was found to have better reactive power controllability; at reduced voltage it can still inject maximum current; there is no potential for creating a resonance point; requires smaller installation space; offers higher availability due to modular design; and can be re-located or expanded easily. The conclusion of deliberations was that for dynamic compensation in Indian power system, STATCOM was preferred over SVC. Reactive power management systems are already being installed at POWERGRID’s 400kV substations at Ludhiana (Punjab), Kankroli (Rajasthan) and New Wanpoh (Kashmir). In addition to the above installations, based on the system study, hybrid solutions of STATCOM along with mechanically switched capacitors & reactors controlled by STATCOM controller have

Figure 4: Principal diagram of VSC-

STATCOM

Figure 6: V–I characteristic of SVC

(top) & STATCOM (bottom)

Figure 5: Installation of ± 200MVAR, 500kV, Containerised STATCOM System



also been considered at selected substations across India (See Table 1). The STATCOM would be primarily for dynamic compensation while the mechanically switched reactors / capacitors would be for reactive compensation under steady state[3].

V. Conclusion From the power electronic industry’s extensive experience with Voltage Source Converter (VSC) technology, it is rapidly becoming the system of choice when selecting modern FACTS and HVDC systems. STATCOM equipment based on VSC technology offers many advantages, the major one being that it exhibits a faster response than the SVC, full current capability even at reduced grid voltage, space saving and modular construction. In the last decade, STATCOM has established a new standard in reactive power compensation technology and has been

gaining popularity over the conventional SVC equipment. For various reasons, electricity grid upgrades, including construction of new transmission lines cannot keep pace with the growing power plant capacity and energy demand. Thus, it is necessary to rely on optimum utilization of existing of transmission & distribution infrastructure by improving the dynamic and steady state stability which can be achieved with the help of reactive power compensation. Any improvement in T&D system stability and efficiency will save precious energy required by our energy starved nation. As both utilities and consumers become more aware of the standards to be maintained and appropriate mitigation techniques, dynamic reactive power compensation will play an increasingly important role in the years to come.

VI. References: [1]http://powermin.nic.in/indian_electricity_scenario/introduction.htm [2] ‘Report on the grid disturbance on 30th July 2012 and grid disturbance on 31st july 2012’, Submitted in Compliance to CERC Order in Petition No. 167/Suo-Motu/2012 dated 1st Aug2012 8th August 2012 [3] CEA Notification No. - 200/10/2013-SP&PA/1287-1339. ‘Study report on dynamic compensations at 13 locations in WR, ER, NR and SR’ as received from POWERGRID.

Table 1: Proposed Installation of STATCOM in Indian Grid [3] Sl. No. Location Dynamic

Compensation (STATCOM)

Mechanically Switched Compensation (MVAR) Reactor Capacitor

Northern region 1. Nalagarh ± 200 MVAR 2 x 125 2 x 125 2. New Lucknow ± 300 MVAR 2 x 125 1 x 125 Western Region 3. Solapur ± 300 MVAR 2 x 125 1 x 125 4. Gwalior ± 200 MVAR 2 x 125 1 x 125 5. Satna ± 300 MVAR 2 x 125 1 x 125 6. Aurangabad ± 300 MVAR 2 x 125 1 x 125 Southern Region 7. Hyderabad (PG) ± 200 MVAR 2 x 125 1 x 125 8. Udumalpet ± 200 MVAR 2 x 125 1 x 125 9. Trichy ± 200 MVAR 2 x 125 1 x 125 Eastern Region 10. Rourkela ± 300 MVAR 2 x 125 - 11. Kishanganj ± 200 MVAR 2 x 125 - 12. Ranchi ± 300 MVAR 2 x 125 - 13. Jeypore ± 200 MVAR 2 x 125 2 x 125


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I. Introduction Electricity is very important and most flexible form of energy and can be converted from most of conventional forms of energy like heat, chemical, potential and kinetic energies. The reverse transformation is also relatively easy in the form of mechanical energy, which can be further translated to potential and kinetic energy, chemical energy, heat energy and also the light energy. Ultra-fast transportation (speed of light), fast and accurate controls make electrical energy superior to any other form of energy. That’s how electrical energy is most preferred form of energy by all segments of consumers. Normally electricity has two basic forms, direct current and alternating current, of which alternating current is most popular due to possibility of voltage transformation using transformers which enhances the capability of handling bulk power at lower costs. Basic idea of converting mechanical energy to electrical energy lies in usage of magnetics/electromagnetics in rotating electrical machines (generators and motors). These rotating machines (generators), using magnetic fields, while driven by mechanical shaft, induces voltage across coils of conducting material (normally referred as inductors), which then becomes the source of electrical energy. Similarly, motors are the main work horses in the industrial sector and form a majority of the electrical loads, consuming electrical power for conversion to mechanical power. Motors also work on the principles of electromagnetics and inductances play a key role in the energy conversion process. II. Understanding Reactive Power: Electrical loads primarily draw power from the source, in the form of electrical

current at near nominal voltage. However, the current lags or leads the voltage based on the characteristics (inductive and capacitive component) of the loads. Inductances and Capacitances store the electrical energy in the form of magnetic energy and static energy and plays significant role in the energy conversion. The component of current in phase with the voltage is responsible for conversion to active power. The power drawn through the component of current which is out of phase with the voltage is source for the reactive power [1]. Though this reactive power does not contribute to the energy conversion/ transformation, it is primarily responsible for maintaining the voltages in the electrical network, in the form of generated e.m.f or back e.m.f in electromagnetic devices. Hence, reactive power is essential part of the electrical systems responsible for desired operation. A. Electrical Systems: Electrical systems can be designed to convert any form of energy to electrical energy, using generators, and then convert back the electrical energy to desired form of energy using loads. The third important component of the electrical systems is the connecting cable between the generators and loads, normally referred as transmission or distribution based on the power handling capacity and the voltage levels. The transformers, voltage transforming devices, are also predominant part of the transmission and distribution system, enabling the operations at appropriate voltage levels. B. Active and reactive powers in

electrical networks: Active power is outcome of the energy conversion process to electrical energy

in the generating stations. Loads of various types consume this active power to convert back electrical energy to mechanical energy, heat energy, chemical energy, light energy etc. There is some energy lost (converted to heat) in the process of transmission and distribution due to resistance of the conducting material. Normally such losses could be of the order of 3-7% depending on the size of the electrical system and the power level it is handling. Most important to note is generator must generate active power as much as required by the loads and compensate for the losses in the electrical systems since electricity cannot be stored (except in batteries) and also there is no transportation/transmission delay in taking power from generator to the loads. Like active power, the reactive power also comes from generator and consumed by load with reactive losses in transmission and distribution network. However, there are more dimensions to the origin of the reactive power. Normally for the transmission lines, in addition to the series inductive reactance which contribute to the reactive losses in the lines, there is line charging capacitance associated with the lines which contribute to the localized reactive generation (spread across the length of the line) of the electrical network. Important to note that line charging is shunt component and proportional to the square of the voltage with respect to the ground. This is ‘hidden’ source reactive power in the electrical networks, especially high voltage lines. Inductive reactance (inductors) are considered to be consuming reactive power and capacitive reactance

Reactive Power Management – An overview Shekhar M Kelapure


(capacitors) and generators in over-excited mode of operation are the sources of reactive power. Inductances of network components are much higher than its resistances (X/R around 4 to 6 for distribution overhead lines and X/R around 10 for transmission). And hence the reactive losses in the electrical network are much higher than active power losses. More to this is like real power losses, reactive power losses are also responsible for drop in voltages at the load end. Since the reactive power sources are mostly of passive type (like capacitance) shunt devices, the output changes as square of the voltages across devices. Every 1% reduction [1] in the voltage brings down reactive support by about 2%, which further reduces voltage till the stabilized value of the system operation. When the transmission and distribution losses in network are predominant, weakening of reactive support to the system is large bringing voltages further down and electrical power system experiences voltage collapse where system reaches unstable operating point with very low voltages across the system striving for the reactive support. Behavior of loads is critical while understanding the reactive power management. Constant impedance type loads are always helping the power system operations recovering from the voltage collapse as against the constant power loads which drag the system towards the voltage collapse. Induction motors even play bigger role and tend to draw more reactive power, especially on low voltage operations than the normal voltage operation. Some power system operators envisage low voltage operation as brown-out for reducing the active power loads and may trap in excessive reactive power demand pulling the system operation to voltage collapse. It is highly recommended to understand the load behavior from active and reactive power perspective before implementing the

load reduction techniques. To minimize the reactive power losses, especially on the longer lines, series capacitors are introduced, to effectively manage the reactive power losses in changing load conditions. Normally, up to 40% compensation of the line is advised to enhance the loading capability of the line. However, shunt and series compensation have impact on the stability of the power system. III. Reactive Power Control via

Power Electronics systems: Reactive power management plays a critical role in the operation of HVDC lines[2]. Heavy controlled reactive power is fed at both ends of the HVDC terminals (especially LCC), i.e. rectifier and inverter. To have accurate and faster control of reactive power (injections as well as absorptions), Static Var compensators, FACTS [3], [4] (Flexible AC Transmission Systems), UPFC (Unified Power Flow Controllers) etc. have been used as shunt & series devices controlled by fast switching devices like Thyristors. These systems have been successfully used to save the power systems from various instabilities.

A. Ferranti effect:

Reactive power is impacted not just by reactive generation and consumption but it is also impacted by real power loading of the system. Especially the long EHV lines, when lightly loaded tend to have over-voltages [5] at the load end of the lines. This is more pronounced while charging unloaded EHV lines when voltages at the far end reach very high values due to the ‘Ferranti effect’. Sometimes bus reactors are used to compensate for the heavy line charging at the EHV sub stations, in addition to the line reactors. Line reactors are primarily designed to compensate for part of the line charging, and normally connected as long as line is in operation.

B. Load reactive Power: Load reactive power is non-linear function of loading as well as voltages applied. Harmonics also plays a role in reactive power consumption. Switching circuits in electronic gadgets introduce non-linear behavior in consumption of reactive power. IV. Conclusion: Reactive Power plays critical role in power system operation. Excessive reactive power consumption leads to more real/reactive losses in the power system, during heavy loaded condition. However, at light loading condition, excessive reactive injections lead to dangerously high voltages. Judicious use of reactive power is essential for the stable and secure operation of the power systems. Reactive injection may improve the power factor for the system, but overcorrection may be dangerous for the operation of the induction motors on the load side. It is very important to understand the pros and cons of reactive power aspects for every application and reactive power management prescription is to be made on case to case basis. References: [1] T. J. Miller, "Reactive Power Control in Electric Power Systems" [2]K.R.Padiyar, “HVDC Power Transmission Systems” [3] Narain G. Hingorani, Laszlo Gyugyi, “Understanding FACTS” [4] Prabha kundur, “Power System Stability and Control” [5] D. P. Kothari, I. J. Nagrath, “Modern Power System Analysis”


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I. Introduction Reactive power is one of the most important ancillary services in electricity market. Reactive power is required for the transmission of active power, control of voltage in the system and normal operation of power systems. Reactive power value and its influence on system stability, especially during hard and congested regimes, can be very high. This article covers the details of reactive power markets and reactive power management in few selected countries. II. India In India, the power distribution companies used to draw large amounts of reactive power from the EHV grid, causing sometimes the voltage to drop to 20% on the 400 kV systems. The Central Energy Regulatory Commission (CERC) [1] has mandated a tariff of 10 Paise/kVArh with effect from 1st April 2010 with escalation at 0.5 paise/kVArh per year thereafter when the voltage dropped below 97% of nominal as part of the Availability Based Tariff (ABT) pricing mechanism. In off-peak periods the charge is reversed with the charge for injecting reactive power when the voltage goes above 103%. In future, reactive power is expected to emerge as an important product in the ancillary service market. III. Canada In Canada each province determines its own electricity policy and hence, the regulatory practices as they relate to the provision and compensation for reactive power. Ontario and Alberta have their own ISOs. In Ontario, all generators of more than 10 MW connected to the grid which are controlled by the Independent Electric System Operator (IESO) are required by the market rules to have the

capability of supplying reactive power at their terminals in the range of 90% lagging (injecting into the system) and 95% leading (absorbing from the system) based on the rated active power at rated voltage. The generators must be capable of operating continuously at full output within ±5% of the generator’s rated terminal voltage. Generators who have signed ancillary service contracts for reactive support and voltage control are compensated for the incremental costs due to energy losses incurred by running at non-unity power factor or costs of running as synchronous condensers at the IESO’s request. They are also compensated for their lost profits if directed to provide reactive capability outside the market rule requirement range. Shunt reactive power compensation equipment, primarily switched capacitors or reactors, are installed by the transmission owner(s) to meet the forecast reactive power requirements as part of their transmission investment programs. In Alberta, generators may be penalized if they are not capable of producing or absorbing reactive power within a 0.90 lagging and 0.95 leading power factor range. These penalties can constrain MW output for a specific period (e.g., six months). In transmission constrained areas where generators provide “transmission must run” service, the contracts include compensation for reactive power. In Manitoba, generators are compensated when they provide reactive power capability outside the normal range specified in the transmission system interconnection or contractual requirements. The compensation mechanism is defined in the interconnection tariff document and is based on generators’ verifiable costs

to provide the extra reactive power. In Québec and British Columbia, the Open Access Transmission Tariff treats reactive support and voltage control as an ancillary service. The cost of providing this service is recovered from the transmission company and paid to the suppliers. Beyond this there are neither incentives nor penalties for the provision of reactive power. IV. United States of America In North America, according to North American Electric Reliability Corporation’s (NERC) Operating Policy 10, only synchronous generators are compensated for reactive power provision. The NYISO uses an embedded cost based pricing to compensate generators for their reactive power services, and also imposes a penalty for failing to provide reactive power. Generators are also compensated for their lost opportunity costs if they are required to produce reactive power by backing down their active power output. Such opportunity cost payments also exist in the PJM Interconnection and the California independent system operator (CaISO) [2]. Provision of reactive power services in the California system is based on long-term contracts between CaISO and reliable must-run (RMR) generators; generators are mandated to provide reactive power within a power factor range 0.9 lagging to 0.95 leading. Beyond these limits, the generators are paid for their reactive power including a loss opportunity cost payment. CaISO’s total payments for the reactive power provided by generators are the sum of short-term procurement payments and payments under long-term contracts. Short-term payments are based on opportunity costs. Long-term payments are made to Scheduling Coordinators that provide voltage supports from RMR units.

Reactive Power Market in Select Countries Rakesha H.S and K. Balaraman


In Texas, generators are required to provide voltage support without compensation in the range 0.95 leading and 0.95 lagging at all times they are online [3]. If the Electricity reliability council of Texas (ERCOT) instructs a generator to reduce its active power output so that it can provide reactive power, that generator will be paid for its lost active energy sales at the higher of the market active energy price for the generator’s zone, the generic fuel cost being applicable to the generator. If system reliability is at risk then there is no compensation. If ERCOT instructs a generator to provide reactive power outside of its required range, ERCOT will pay for the additional reactive power at a price that recognizes the appropriate avoided cost of reactive support resources. V. United Kingdom In the early 1990s, after privatization and corporate unbundling of generation, transmission and distribution, the England-Wales market started with a cost-reflective (cost-based) approach to paying generators for reactive power. Since the mid-1990s, a market-oriented approach to reactive power has evolved. Generators with a capacity greater than 50 MW are required to have a 0.95 leading power factor to a 0.85 lagging power factor capability at the high voltage side of the generator step-up transformer. After extensive consultation with market participants, metering and monitoring rules were established and new dispatch rules were developed. The National Grid Company (NGC), which is both the system operator and the transmission owner, sends the generator a dispatch signal consisting of the amount of active power and reactive power within a range of the generator capability. A generator can accept a default payment for reactive power of approximately £2.40/MVArh leading or lagging, or as an alternative, the generator may offer contracts with a

minimum term of one year. The offer consists of three parts: a synchronized capability price in £/ MVAr, an availability capability price in £/MVAr and a utilization price in £/MVArh. The grid company assesses the offer, historical performance and effectiveness of each generator against its locational forecast needs in about 20 electrical zones to decide which offers to accept. This provides generators with incentives to offer capability beyond the requirements, lowering investment requirements for the transmission system. The NGC has financial incentives to keep congestion low. Since the year 1990 the company increased its transmission reactive power capacity from about 3,000 MVArs to about 19,000 MVArs of mechanically switched capacitors, 9,000 MVArs of SVCs and 4,000 MVArs of Quadrature Boosters (similar to phase shifters) by the year 2004. Some of the SVCs can be relocated by truck in about eight months. In contrast to conventional approaches, NGC relocates some of the transmission assets in order to provide relief to areas in need. Twenty percent of the reactive power supplied is from generators. VI. New Zealand In New Zealand, need for voltage support beyond minimum requirements is almost entirely limited to the Auckland region. ‘Transpower’ has a few long-term supply contracts, with generators which provide such additional voltage support to be provided under certain circumstances. The pricing of this additional supply depends upon the source, and for generators usually includes the opportunity cost of foregone active power sales. Transpower’s payments under these contracts form part of the cost of purchasing voltage support ancillary services. The current annual cost for voltage support is approximately US $3.4 million.

VII. Japan In Japan, Tokyo Electric Power Company (TEPCO) gives their retail customers the financial incentive to improve their power factor. It comes in the form of a discount of the base rate. The discount is based on the customer’s power factor. The electricity rate is a two part tariff: Base Rate + Electricity Rate, Where Base Rate = (Unit Price [Yen/kW])*(Contract kW)*(1.85-Power Factor) Electricity Rate = (Unit Price [Yen/kWh])*Total Usage [kWh] Unit Price for Base Rate is about US$ 10/kW and Unit Price for Electricity Rate is about US¢10/kWh. This program results in load installing equipment to increase its power factor and hence, reduce the base rate. Under this tariff the average customer power factor is 0.99. VIII. Conclusions Reactive power management and reactive power pricing has become an important issue in the electricity industry. There are various market mechanisms to control the voltage and manage reactive power being followed in many countries. It is noted that reactive power as one of the ancillary service is expected as a main product in Indian electricity market within a few years’ time. This article gives an initial insight to the readers to understand the market mechanisms in various countries and to deliberate on the emerging ancillary service market in India with reactive power support as a major product. It is important that reactive power pricing mechanism shall be made part of the ancillary market so as to establish a transparent process to make users to understand and participate. References [1]“Indian Electricity Grid Code Regulations, 2010” Central Electricity Regulatory Commission


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[2]“Firm Conduct in California’s Deregulated Electricity Market,” Steven L.Puller. [3] “Reactive Power Delivery Incentives Harvard Electricity Policy Group,” 12/2/04 Alan Robb VP Operations Grid America LLC. Further reading [1] “Principles for Efficient and Reliable Reactive Power Supply and Consumption,” Staff report, Federal Energy Regulatory Commission. [2] “Issues for Reactive Power and Voltage Control Pricing in a Deregulated Environment,” A. P. Sakis Meliopoulos, Murad A. Asa’d G. J. Cokkinides School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta. [3] “A Unified Framework for Reactive Power Management in Deregulated Electricity Markets,” El-Samahy, K. Bhattacharya, and C. A. Cañizares. [4]“Reactive Power as an Identifiable Ancillary Service.” Prepared for Transmission Administrator of Alberta, Ltd. March 2003. Alvarado, F., Borissov, B., Kirsch, L. D. [5]“A Computational Algorithm for Real-Time Control of System Voltage and Reative Power – Part 1 Problem Formulation,” S. Narita, M. S. A. A. Hammam Clarkson College of Technology, Potsdam, New York. [6] “Pricing of Reactive Power Service,” R. Deksnys, R. Staniulis ISSN 0208- 189X. [8] “Reactive Power Support Services in Electricity Markets,” by PSERC Publication 00-08.

M/s Power Research and Development Consultants Pvt. Ltd. (PRDC) have successfully completed the job of carrying out power quality analysis for an oil & gas plant in Qatar with emphasis on reactive power management and harmonic analysis. The study has been carried out for a synthetic fuel plant that uses gas to liquids (GTL) technology for converting natural gas into liquid petroleum products. Gas to Liquids (GTL) takes natural gas and converts it to low-sulphur environmental friendly diesel, naphtha, and LPG. The total in house generation capacity of the plant is 57.75MW in which 2 X 26.775MW and 1 X 2.5MW are connected at 11kV. Besides, another 2 X 0.85MW is connected at 6.6kV. The plant is connected to grid substation at 33kV level. The total load (linear and non- linear) of the plant is distributed at 6.6kV and 0.415kV voltage levels. Reactive power management studies have been carried out to assess the capability of plant generators to meet the reactive power requirements of the plant load. As part of this, detailed

conditions of the plant have been studied to determine additional reactive power compensation required in the plant. Capacitor banks have been recommended at main receiving substation in order to meet the reactive power requirement of loads in the plant and also to reduce the reactive power burden on the in-plant generators. Detailed harmonic analyses have been carried out using the harmonic measurements made at various voltage levels of the plant with a view to ascertaining if the harmonic distortions are within the levels as specified in the IEEE Std. 519 (IEEE Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems). Based on detailed analysis, it was recommended to tune the proposed capacitor banks to 5th harmonic frequency considering existing current harmonic spectrum and the impedance characteristics of the plant for the particular frequency band under study.

Consultancy Services Rendered

Reactive Power Management & Harmonic Analysis for Oil & Gas Plant in Qatar


I. Introduction Information technology (IT) companies are playing a key role in India’s power distribution sector through the Centrally-sponsored Restructured Accelerated Power Development & Reforms Programme (RAPDRP), launched by the Ministry of Power, Government of India under its 11th five year plan. The programme promises to reduce AT&C losses to 15% across major towns and cities. RAPDRP has now been subsumed in the newly launched inegrated power development scheme (IPDS). II. Project Details Projects under the RAPDRP scheme were taken up in two parts. Part-A included the projects for establishment of baseline data and IT applications for energy accounting/auditing and IT-based consumer service centers. Part-B included regular distribution strengthening projects. The activities covered under each part are as follows: Part A: Preparation of base-line data for the project area covering consumer indexing, GIS mapping, metering of distribution transformers and feeders, and automatic data logging for all distribution transformers and feeders and SCADA/DMS system (only in the project area having population exceeding 4 lakh and annual input energy of the order of 350 million kwh). It includes asset mapping of the entire distribution network at and below the 11kV transformers and feeders, low tension lines, poles and other distribution network equipment. It also includes adoption of IT applications for meter reading, billing & collection; energy accounting & auditing; MIS; redressing consumer grievances; establishment of IT-enabled consumer service centers etc. The base line data and required system are to be verified

by an independent agency appointed by the Ministry of Power. Part B: Under this, system strengthening measures like renovation, modernization and strengthening of 11kV level substations, transformers, reconductoring of lines at 11kV level and below, load bifurcation, feeder separation, load balancing, HVDS, aerial bunched conductoring in dense areas, replacement of electromagnetic energy meters with tamper proof electronic meters, installation of capacitor banks and mobile service centers etc. are to be implemented. In exceptional cases, where sub-transmission system is weak, strengthening at 33kV or 66kV levels may also be considered. It may be mentioned that R-APDRP is applicable only to towns that have a population of 30,000 or more (10,000 or more in the case of Special Category states) and

where ATC losses are above 15%.

III. Success Story of Gujarat : Gujarat has become the first among all the Indian states to have its data center (DC) for R-APDRP commissioned. The system integrator namely, TATA Consultancy Services has set an example by implementing efficient software application for complex business processes and integrating the same on a common software / hardware platform. These applications were installed and commissioned stagewise in the selected pilot towns from each of the Discoms as

given in Table I.

Given below are the details of applications implemented to facilitate

Table I: Towns implementing IT applications under RAPDRP in

Gujarat Discom Pilot Town MGVCL Anand DGVCL Vyara PGVCL Dhoraji UGVCL Viramgam

Power System tools developed by M/s PRDC Pvt. Ltd. On ESRI (GIS software)

user Interface

Consultancy Services Rendered


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Discom business. 1. Geographic Information System (GIS) All network assests, like, HT & LT Line, poles, consumers, transformers, are mapped as per their actual location. Planning a new network has become very easy, as all network can be seen on actual geographical map. Consumer indexing was the toughest work to finish in this programme without compromising it’s authenticity. But gradually with proper data checking, correctness of consumer indexing came to a proper shape. Error free data gives correct result; otherwise all analysis related network loading, energy audit, consumer billing will not be accurate, which will also impact on AT&C loss calculation. GIS also needs to be in sync with other applications, i.e: if any changes in assets occur in field, same should be updated in application. As GIS act as mother data base for all assets, any updation in other application like MDAS and CRM should be mapped in GIS & vice-versa. 2. Network Analysis (NA) It is perhaps for the first time in India, GIS has got applications into power domain throgh RAPDRP. M/s PRDC Pvt. Ltd. has achieved a milestone by integrating power system applications to GIS. Just on mouse click, network conditions could be seen in monitor screen and all information related to over loaded area, under voltage area, etc. can be extracted. Users can do financial analysis for network expansion plan more accurately with less effort. Loss calculations are performed through this application and shared with other application to perform energy audit. Engineers can now plan their network in an optimal way by using power system analysis tools developed by PRDC. 3. Distribution Planning Tools under NA to assist decision

support system towards technical improvement: a) New Connection The aim is to enhance the convenience of the customer when an application for new connection is received. The system would enable updating customer data to be captured in GIS based customer indexing database in a reliable way and perform load flow analysis with proper validation to check the system feasibility for approval of new connection. b) Technical loss computation for Energy audit A part of Energy Accounting where Technical Losses of the distribution system is calculated with actual meter data. An integrated system with MDM is developed which uses the load flow analysis results for assessing the actual technical energy loss. c) Financial analysis - Cost estimation/Present worth This system supports analysis of

commercial feasibility of proposed work for network enhancement. Preparation of cost estimates, evaluation of internal rate of return and payback period can be done using proper input parameters. Few ‘what-if’ analysis tools that allow user to discover an optimized solution to augment the existing network for reduced technical losses are as follows: • Line Reconductoring • Network reconfiguration • Transformer relocation Besides the above, few more applications namely, Customer relationship management (CRM), Meter Data Acquisition System (MDAS) and meter data management (MDM) heve been provided by the system interators utilizing the capabilities of Network analysis solutions of PRDC.

MSETCL awards WAMS & Smart Grid Consultancy to PRDC Consortium

Maharashtra State Electricity Transmission Co. Ltd.(MSETCL) awarded job of providing consultancy services for ‘Preparation of Road Map for Implementation of SMART GRID and implementation of Wide Area measurement System (WAMS)’ through separate tenders to PRDC in consortium with M/s Pentacle Solutions Pvt. Ltd. MSETCL intend to transform the existing Transmission grid of Maharashtra into a more efficient, reliable, safe and less constrained grid that would help provide access to electricity to all using Smart Grid Technology. The purpose of the assignment is to make the existing grid infrastructure as efficient and robust as possible, through the use of intelligence and automation, by encouraging active supply and demand-side participation and by promoting innovative business practices and regulatory environments that provide incentives for efficient production, transmission, distribution and consumption of electricity across the entire value chain. PRDC, in this assignment will perform As-Is Study, prepare Road-Map, Detailed Technical Specification document, DPR and RFP for implementation of WAMS and Smart Grid in Maharashtra Transmission system.


PRDC organized a one day seminar

on ‘Smart grid, Wide Area Measurement System and GIS’ for MSETCL personnel at Hotel Sofitel, Mumbai on October 8, 2014. Faculty for the seminar included Dr. R. Nagaraja, Mr. M.M. Babu Narayanan, Dr. Shekhar M. Kelapure & Mr. Faraz Khan of PRDC. Seminar was inaugurated by Shri Bipin Srimali, CMD, MSECTCL. There were about 25 participants consisting of senior officers of MSECTCL.

PRDC participated at the “I for Africa” Conference & Exhibition organized by Indo-African Chamber of Commerce & Industries. The conference was held at ITC Maratha, Mumbai during 10 – 12, October 2014. Delegates from more than 25 African countries participated in the conference. Delegates included various Government agencies and Consulates of Africa.

There were large number of visitors to the exhibition stall put up by PRDC who evinced keen interest to explore business opportunities with their respective countries.

CESU, Odisha has selected PRDC as

its consultant for preparation of DPR for creating Ring system network in RRCP scheme among all the 33/11 kV sub-stations under its jurisdiction.

M/s Adani Group, has placed the

order on PRDC for supply of Power System Analysis and Simulation tool – MiPower™.

M/s JSW Steel Works, Dolvi have

selected PRDC to carry out the Grid Islanding studies for their Dolvi plant.

PRDC – ASAS consortium has

bagged the order from Worley Parsons for providing consultancy services for Electromagnetic Switching Transients & Insulation Coordination Study for Luke Oil project.

Seminars/Workshops

Events & Achievements Achievements

Visitors at PRDC Stall in “I for Africa” Conference & Exhibition held at ITC

Maratha, Mumbai

Seminar on Smart grid, Wide Area Measurement System and GIS for MSETCL,Mumbai


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NPSC -2014

At PRDC, we conduct various training programmes throughout the year. The duration of the training programme varies from one to four weeks. One Week Training We conduct one week training programme on MiPower™. It is a standard course. MiPower Training Level 1 Level 1 is a training programme on basic theory & simple problems (hands - on). Level 1 Batch: 19th January to 23rd January 2015. MiPower Training Level 2 Level 2 is a training programme which consists of only hands-on and solving own system problems, sorting out issues and clarifications. Level 2 Batch: 9th February to 13th February 2015. Short Term Training /Workshop In addition to the above said programme PRDC is also conducting short term training program and workshops to impart knowledge and practical approach on specific topics, which are of relevance to power engineers in day-to-day works. Such training not only enhances their knowledge but also helps to implement these techniques in their routine works. For short term and special training programme, please contact our marketing team at the following address: [email protected]

PRDC was one of the gold sponsors of the 18th National power System Conference (NPSC-2014) hosted by the Department of Electronics and Electrical Engineering, IIT Guwahati during December 18- 20, 2014. The main theme of the conference was "Towards greener, smarter and reliable electricity systems" PRDC engineers presented two technical Papers in the conference which are as follows:

• Nitesh Kumar D, R. Nagaraja and H.P Khincha, “A Comprehensive Protection Scheme for Generator Loss of Excitation”. • Faraz Zafar Khan, R. Nagaraja and H. P. Khincha, “Improved Fault Location Computation using Prony Analysis for Short Duration Fault”.

Our Expertise in Training Upcoming Events

Dr. R. Nagaraja, MD, PRDC delivering plenary talk on “Recent Advancements in Power System Protection” at NPSC conference in Guwahati


We at PRDC firmly believe that all our associates are the champions of our growth. PRDC has highly qualified professionals from the prestigious institutes in the country and has been nurturing a wonderful work culture. Our motto is to provide opportunity to learn at work place, employee friendly policies, Leadership programs and employee welfare facilities. The 20 years of our organization’s growth have honed the leadership skills in our Management team across various domains and nurtured our young and budding talents to make a rewarding career with us. Equal opportunities at all levels, induction and socializing, employee friendly policies have been the key factors for our employee branding to attract new and niche talents. Campus pooling is a yearly program, where invitations are sent to top-notch colleges across India including the IITs and IISc. In the first quarter of this financial year 2014-15, we had campus pool recruitment with around 625 students from department of Electrical & Electronics engineering, participating to join the talent force. The recruitment process is very fair and the candidates are shortlisted based on performance and behavioral based interviews. The new recruits had a rigorous two months’ in-house training on the core topics that are required for the projects that we work and based on the business requirements. Few of them have been inducted into the R&D team of PRDC for carrying out developmental activities. Apart from on-job training programs, periodic lectures by the Senior Consultants from the Industry are being organized which will enhance and sharpen the skills of the team to handle critical projects.

We have a team of around 200+ electrical engineers who work on various Industry and utility related projects in the areas of Power Systems under one roof. We also have experienced and thorough software professionals and a strong embedded systems group to cater to the challenging needs of the power industry. VTU Research Centre in PRDC PRDC encourages the young talents to pursue higher studies; In pursuance of this objective, it was awarded recognition as a Research Centre under Visvesvaraya Technological University (VTU) of Karnataka. We offer M.Sc. (Engineering) and PhD through research programme. Currently we have four of our engineers pursuing their Masters in Power Systems and four others are pursuing their PhD in Power Systems. Besides, these eight PRDCians, there are four more external candidates registered with this Research centre. Through research programs, we encourage our employees to publish technical papers in the journals/ conferences. Papers published in referred national/international journals are specially rewarded by PRDC through cash awards & citations. Recently published papers: • Chandra Shekhar Reddy Atla and Dr. Balaraman K, “Generation Planning for Interconnected Power Systems with High Wind Penetration Using Probabilistic Methods”. International Journal of Electrical Engineering, Romania (accepted for publication) • Nitesh Kumar D, R. Nagaraja and H P

Khincha, “A Comprehensive Protection Scheme for Generator Loss of Excitation”, NPSC – 2014, IIT Guwahati, December 2014 • Faraz Zafar Khan, R. Nagaraja and H. P. Khincha, “Improved Fault Location Computation using Prony Analysis for Short Duration Fault”, NPSC – 2014, IIT Guwahati, December 2014. Employee engagement programme The employee engagement programs like team building and leadership programs are inculcated for the personal growth of employee. This quarter was a special one with several key senior members completing ten successful years in delivering value year-on-year in line with the company’s vision & mission. Encouragement is synonymous with PRDC as we encourage our engineers to innovate and come up with new ideas, new designs and concepts. In this context, we have almost completed development of a product to be launched very soon which was an intuitive idea of a senior and creative member of PRDC family. We always have an open door policy. Suggestions are appreciated and discussed during the brainstorming and knowledge transfer sessions for quick implementation. On the whole, working at PRDC would be great fun with no fuss!

HR @ PRDC


Newsletter

Deen Dayal Upadhyaya Gram Jyoti Yojana The Central Government has decided to introduce and implement Deen Dayal Upadhyaya Gram Jyoti Yojana in the country. Deendayal Upadhyaya Gram Jyoti Yojana [DDUGJY] envisages feeder separation, strengthening of sub-transmission and distribution system including metering of distribution transformers/feeders/consumers and rural electrification with scheme cost of Rs.43033 crore during the entire implementation period. The scheme implementation starts in current Financial Year 2014-15. The scheme would help in:

(i) Improvement in hours of power supply in rural areas

(ii) Reduction in peak load

(iii) Improvement in billed energy based on metered consumption

(iv) Providing access to electricity to rural households.

Source: pib.nic.in

Integrated Power Development Scheme

The Union cabinet gave approval for "Integrated Power Development Scheme" (IPDS) with the following objectives:

(i) Strengthening of sub-transmission and distribution network in the urban areas

(ii) Metering of distribution transformers /feeders / consumers in the urban areas (iii) IT enablement of distribution sector and strengthening of distribution network.

Union government also gave approval for completion of targeted works laid down under the Restructured Accelerated Power Development and Reforms Programme (RAPDRP) for 12th

and 13th Plans by carrying forward the approved outlay for RAPDRP to IPDS. The scheme will help in reduction of

AT&C losses, establishment of IT enabled energy accounting / auditing system, improvement in billed energy based on metered consumption and improvement in collection efficiency.

Source: pib.nic.in

Action Plan to Minimize Electricity Consumption The Union Government is implementing Policies/Programmes during the 12th Five Year Plan to promote energy efficiency and also implementing activities under National Mission for Enhanced Energy Efficiency (NMEEE) to minimize electricity consumption. To promote use of energy efficient appliances, Bureau of Energy Efficiency (BEE) initiated Standard & Labeling (S&L) Programme during 11th Five Year Plan. The key objectives of the S&L Programme is to label energy consuming appliances on the basis of their energy consumption data so as to provide an informed choice to the consumers about energy and cost saving potential of the household and other appliances.

Source: pib.nic.in

Power System Development Fund (PSDF) Power System Development Fund (PSDF) was been constituted vide Central Electricity Regulatory Commission (Power System Development Fund) Regulations, 2010 dated 4th June 2010. National Load dispatch centre will be the nodal agency for PSDF.

“Power System Development Fund (PSDF) will be utilised for creating necessary transmission systems of

strategic importance based on operational feedback by Load Dispatch Centres for relieving congestion in Inter-State Transmission Systems. The fund will also be utilised towards installation of shunt capacitors, series compensators

and other reactive energy generators for

improvement of voltage profile in the grid, installation of standard and special protection schemes, pilot and demonstrative projects, and for setting right discrepancies identified in protection audits on regional basis and renovation and modernisation (R&M) of transmission and distribution systems for relieving congestion and any other scheme or project in furtherance of the above objectives, such as, conducting technical studies and capacity building.

As per the latest directive of the Government of India, Ministry of Power, the the process of disbursement of Funds and management of PSDF has been entrsuted with an Appraisal Committee and Montoring Committee.

Source: http://psdfindia.in/

Solar Parks The Ministry of New & Renewable Energy has initiated scheme for setting up of 25 Solar Parks, each with the capacity of 500 MW and above, to be developed in next 5 years in various States. The states identified are Gujarat – 750 MW, Madhya Pradesh – 1500 MW, Telangana – 1000 MW, Andhra Pradesh – 2500 MW, Karnataka – 1000 MW, Uttar Pradesh – 600 MW, Meghalaya – 50 MW, Jammu & Kashmir – 7500 MW, Punjab 2000 MW, Rajasthan – 3700 MW, Tamil Nadu – 500 MW and Odisha – 1000 MW.

Source: pib.nic.in

Indian Power Sector Highlights


Dr.K. Balaraman, M.Tech, (Ph.D) worked for BEML at their R&D division. After a brief stint, he joined Karnataka Electricity Board

(now Karnataka Power Transmission Company Limited – KPTCL) in 1992 as Assistant Engineer. . In 1997 he was awarded BRITISH OVERSEAS SCHOLARSHIP by CONFEDERATION OF BRITISH INDUSTRY to undergo practical training in NATIONAL GRID COMPANY PLC. England. In 2007, he was awarded Doctorate by Visvesvaraya Technological University in the subject of “Developing New Methodologies in Energy Management System”. In 2006, he joined Power Research Development Consultants Pvt.Ltd as General Manager (Power System studies). Currently, he is the Chief General Manager at PRDC heading the Power Systems Studies group.

Mr.Lalit Tejwani has 23 years of

international experience in areas of power

electronics, automation,

electrical engineering. He obtained B.E.(Elect) from Pune University, India in 1991, and completed Diploma in Business Management in 1992. From 1994 to 2007 Lalit was based out of Singapore. He worked for SIEMENS, Singapore responsible for business in South East Asia. From 2007 to 2012, he

was with ABB Limited. He is a member of IEEE, Power & Energy Society. Currently, he is heading operations of Rongxin Power Electronic (RXPE) India Pvt Ltd, based out of Kolkata. RXPE manufactures of FACTS, STATCOM, MV– HV DC, Energy Storage, and other high power electronic equipment for utilities and industrial sectors.

Dr. R. Nagaraja is the founder and Managing Director of M/s. Power Research &

Development Consultants Pvt.Ltd., Bengaluru. Nagaraja

has done his B.E. in Electrical and Electronics Engineering from Mysore University (India) in 1986. He obtained his M.E in 1988 specializing in Computer Applications to Power System and Drives and Ph.D. Degree in the field of Energy Management System from Indian Institute of Science (IISc). Dr. Nagaraja has authored several technical papers and conducted a number of workshops / conferences/ seminars throughout the country. Dr. Nagaraja is the brain behind the architecture, design and development of the MiPower™ – Power system analysis software package. Dr. Nagaraja has been involved in the planning studies of State Utilities and Industries in India and abroad.

Rakesha H S obtained B.E. (E&E) degree from BDT college of engineering, Davangere

formerly affiliated to Kuvempu University, Karnataka. He joined in PRDC in 2005 as Engineer-PSS and involved in carrying out power evacuation studies for various IPPs and utilities, transmission planning and master plan preparation of various utilities in India and abroad. His areas of interest are power system studies mainly in the area of power system operation, planning, regulations and electricity market. He is presently working as Manger, power system studies at PRDC.

Dr. Shekhar Kelapure (IEEE SM’04) received BE Electrical from Pune University, 1992 and M. Tech and PhD from Indian Institute of Technology, Delhi

in 2000. His areas of expertise include Power System Analysis and Optimization, Security Assessment, Grid Operations and SCADA/EMS/DMS. He worked as Senior Scientist with GE Global Research, Bengaluru from 2010 to 2014. Currently working as a General Manager (R&D) in Power Research and Development Consultants Pvt Ltd, Bengaluru and responsible for various activities related to research and consulting in the domain of Power System and also mentoring the students for their Masters and PhD work.

About the Authors

Lalit Tejwani

Dr. K. Balaraman

Rakesha H S

Dr. R. Nagaraja

Dr. Shekhar M. Kelapure


Newsletter

R.N.I No. KARENG/2013/51589

Printed & Published by : Dr. R. Nagaraja on behalf of Power Research & Development Consultants Pvt. Ltd.Printed at : M/s. Art Print, Dr. Modi Hospital Main, WOC Road, Bangalore - 560 086. Cell : 98452 33516. Editor : M.M. Babu Narayanan

Power Research & Development Consultants Pvt. Ltd.# 5, 11th Cross, 2nd Stage, West of Chord Road,

Bangalore - 560086. INDIA. Phone : (080) 4245 5555 / 2319 2209Website : www.prdcinfotech.com

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