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Enhancement of Available TransferCapacity

for

Congestion ManagementIn

Deregulated Power SystemGuided by :

Prof. S. K. JoshiM.S.U. Baroda

Presented byB.P.Pandya , BE(E) IV

Roll No. : 424

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Project Theme

Deregulated Electricity Market Open Access

Congestion Management

Available Transfer Capacity

To propose a new set of AC sensitivity referred as ACPower Transfer Congestion Distribution Factor (ACPTCDF)

for 6 bus system.

Calculate ATC of transmission line

Enhancement of ATC using facts devices forcongestion management

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Significance of Topic

Conversion of Vertically integrated utilities to Open Accessmarket system

[ May 2003,Indian Electricity Act]

To promote competition through open access among utilities

ATC must be calculated [ ATC posted on OASIS] Because of Open Access, Congestion is prime problem for

power system

Congestion can be managed by Facts devices. Fact devicescan enhance ATC.

So we develop a set of congestion distribution factors in termsof real as well as reactive power

Most sensitive congested line is identified by sensitiveanalysis and ATC calculation

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Regulation

Regulation means thatthe Government has set

down laws and rules thatput limits on and definehow a particular industryor company can operate.

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Deregulation

Deregulation inpower industry is arestructuring of the

rules andeconomicincentives thatgovernment set upto control and drive

electric powerindustry.

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Advantages of Deregulation

The need for regulation changed former verticallyintegrated utility is disaggregated into separatecompanies devoted to each function.

Privatization Cost is expected to drop

Customer focus will improve

Encourages innovation

Power production and retail sales will be competitive,monopoly franchise business

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Benefits & Issues involved in Deregulation

Benefits Issues

Improved generation Network Congestion

Planning Efficiency Optimal bidding for Genco

Cheaper electricity due tocompetition and innovation

Transmission pricing

Improved Economy Ancillary Services

ManagementNew jobs for powerengineers

Risk Analysis

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Network Congestion

When the producers and consumers of the electricenergy desire to produce and consume in total thatwould cause the transmission system to operate at orbeyond one or more transfer limit, the system is said to

be congested.

Congestion is a consequence of network constraintscharacterizing a finite network capacity that prevent thesimultaneous delivery of power from an associated set ofpower transactions.

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Constraints

Thermal limit :- The maximum amount of electrical energythat transmit on transmission line without

overheating.

Voltage limit :- System voltage and change in voltage must

be maintained with the range of acceptable

deviation

Stability limit :- Transmission system capable of survivingdisturbances through the

transient and dynamic period

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Graph showing congestion

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Objective of Congestion Management

Minimized interference of the transmission network in themarket for electric energy

Secure operation of the power system

Improvement of market efficiency Manage power flow with existing Transmission line

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Available Transfer Capacity (ATC)

ATCis a measure of the Transfer Capability Remaining inthe transmission network for further commercial activity*over and above already committed uses

(* while ensuring system security)

Mathematically,ATC = TTC TRM (ETC+CBM)

[In accordance with the recent FERC (Federal Energy Regulatory Commission) Order 888(Promoting Utility Competition Through Open Access, Non discriminatory Transmission service

by Public Utility)& 889(OASIS , Open Access Same time Information system) ,ATC must be calculated for electric utility]

.

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ATC = TTC TRM (ETC+CBM)

ETC is the existing transfer commitments

TTC is the maximum amount of power which can betransferred over the network while satisfying all securityconstraints.

TRM is the margin required for uncertainties in the systemconditions.

CBM is the margin reserved by load serving entities forgeneration reliability requirements.

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Pre- Contingency Situation

Bart.SE

NrthBarth.

N.E.S. Delaware

Flow 900

Flow 50

Rating 210

ContingencyElement

CONTINGENCY

Flow gate direction

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Post contingency situation

N.E.S.Delaware

Flow 0

Flow 212

Rating 210

contingency

50 + 0.18 * 900

Flow gate direction

BartSE

NrthBart

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Transfer Capacity on 28/4/2010

Present Status: Transfer Capacity state

1. Congestion charges applicable NO

2. Total transfer capacity(TTC) of NR 4250 MW

3. Available transfer capacity(ATC) of NR 3750 MW

4. IR Schedule 2749 MW

5. IR Actual 2930 MW

6. TTC Violation -1320 MW

7. ATC Violation -820 MW

NORMAL

Transfer capacitystate

1) Normal- NoViolation- colorGreen

2) Alert- ATCViolation- colorYellow

3) Emergency- TTCViolation- colorRed

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Role of ISO

ATC is a measure of how much additional electricpower could be transferred.

Each ISO is responsible for monitoring its own regionaltransmission system and calculating ATC for potentially

congested paths.

ATC values would be placed on a website known asOpen Access Same-time Information System (OASIS)operated by ISO.

Anyone wishing to do transaction, would access OASISweb pages and use ATC information available there todetermine if system could accommodate the transaction.

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Methods ofATC

Calculation

Using PTCDFand LODF

Optimal powerflow method

Continuationmethod

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AC Load flow based Approach

A.C. based approach utilized two sets of sensitivityfactors terms as Real Power Transmission CongestionFactor (PTCDF) & Reactive Power TransmissionCongestion Factor (QTCDF)

Most sensitive transmission line can be found & managethis line with use of FACTS device.

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Real Power Transfer Congestion DistributionFactor ( PTCDF)

For ATC determination the MW flow must be allocated toeach line or group of lines in proportion to MW beingtransmitted by each transaction.

A transaction is a specific amount of power that isinjected in to the system at one bus by a generator &removed at the another bus by load.

PTCDF is defined as the change in real power flow (Pij)

in a transmission linek, connected between bus i & j,due to unit change in the power injection(Pn) at bus-n.

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QTCDF is defined as the change in reactive power flow

(Qij) in a transmission linek, connected between bus i& j, due to unit change in the reactive powerinjection(Qn) at bus-n

It is also called sensitivity because it relates the amountof one change transaction amount to another change line flow.

1 52 34 76

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ATC Calculation using PTCDF

Recognizing new flow on line from bus i to bus j (line k)due to transaction at bus n.

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Line Outage Distribution Factor (LODF)

ATC is also limited by the effects of contingencies. The line flows could be used to calculate the effect of

each line outage, then PTCDF applied to find transferlimit.

LODFs & PTCDFs can be combined to calculate thefirst contingency incremental transfer capability, which isthe maximum increase in transaction amount from onebus to another bus.

LODF can be defined as the measure of redistributionbecause of line outage.

1 2 3 4 5 6

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ATC using PTCDF & LODF

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Congestion Management by FACTS devices

For efficient utilization of the existing network withpenetration of additional power FACTS devices areused.

Effective FACTS based power flow control can beapplied to relieve transmission congestion & Improve thetransfer capability of the network with high penetration ofpower. While voltage security & voltage stabilityconstraint are satisfied & transmission net work can beeffectively utilized.

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Principle of Control The inserted series voltage can be regulated to change

the impedance (X) of Transmission line hence powerflow of the line can be controlled.

FACTS is power Electronics based system that providedynamic control of the power transfer parameters

transmission voltage, line impedance & phase angle,active and reactive power when storage becomes viablestorage then they can supply & absorbed active poweras well

Consider unity power factor load, real power transferredis given by

Similarly Reactive power transferred is given by

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FACTS Technology and their potential

Definition[3] of FACTS by IEEE as:

Alternating current transmission system incorporatingpower Electronics based & other static controller toenhance controllability and increase power transfercapability

FACTS controller [14] :- It is power electronic-basedsystem and other static equipment that provide control of

one or more AC transmission parameters.

For ATC enhancement the FACTS devices are placedat weak-bus.

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FACTS Devices

1. Shunt controller :Adjusting the system voltage by means of shunt

reactive elements is known as shunt compensation.

2. Series Controller :

Adjusting the system voltage by means of series reactiveelements is known as shunt compensation.

3. Combined shunt-series controller (Unified Power FlowController) :-

It provides independent series reactive compensation for

each line bus also transfer real power among the line viad.c. power link (Inter line power flow controller).

Used in multiple line

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FACTS DEVICES LOCATION

We look at static considerations here for the placement of FACTSdevices in the power system. The objectives for device placementmay be one of the following:

1. Reduction in the real power loss of a particular line

2. Reduction in the total system real power loss 3. Reduction in the total system reactive power loss

4. Maximum relief of congestion in the system

For the first three objectives, methods based on the sensitivityapproach may be used. If the objective of FACTS device placement

is to provide maximum relief of congestion, the devices may beplaced in the most congested lines .

For ATC enhancement the FACTS devices are placed at weak-bus.

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Weak Bus Identification

The basic equations used in N-R Load flow are given below

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To obtain real and reactive power sensitivity, the basic load flow equations becomes

(3)

Hence, the real and reactive power sensitivities of the ith

P P

P V

VQ P Q

V

2

4

bus are obtained as

(4)

ii

ii

i

i

i

ii

i

PJ V

V

QJ V

V

..continue

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..continue

i

Eq.4 represents the real and reactive power sensitivities of the i-th bus.

deg

, min change in V for variation

in Q-sta

thi i

i i

Q Qalso indicatethe ree of weakness for i bus as being

V V

high becomes low indicating imum

tus of the bus. Thus, being higher,

the degree of weakness of the i-th bus becomes lesser

i

i

Q

V

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N

Y

Start

Run Base case Load flow

Form full jacobian except for the SlackBus

Consider Transaction

Identify seller and buyer busesi & j

Compute Line flows

Compute the JacobianInverse

Compute ACPTCDF & LODFusing same transaction

Are alltransaction over

Go to newtransaction

Inject Reactive power withFACTS devices

Calculate AvailabilityTransfer capability & print

Results

End

Flow chart

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Results for 6 bus system

(2) Results of basic load flow :

(3) (a) Line flows file : line_flow.txt

From to --- Line flows ---- ------- Line loss--

MW MVar MVA MW MVar

1 2 -18.37627 292.961 293.537 28.955 53.869

1 5 5.30588 95.595 95.742 3.185 1.840

2 1 47.33095 -239.092 243.732 28.955 53.869

2 4 7.66905 -116.081 116.334 6.499 9.378

3 5 0.73076 -36.339 36.346 0.472 -3.1673 6 35.26924 10.639 36.839 0.561 -2.782

4 2 -1.17022 125.459 125.464 6.499 9.378

4 5 34.07616 -51.782 61.988 1.456 -1.199

4 6 67.09406 -3.723 67.197 1.802 -0.302

5 1 -2.12073 -93.755 93.779 3.185 1.840

5 3 -0.25888 33.172 33.173 0.472 -3.1675 4 -32.62039 50.583 60.189 1.456 -1.199

6 3 -34.70777 -13.421 37.212 0.561 -2.782

6 4 -65.29223 3.421 65.382 1.802 -0.302

Total Loss 42.930 57.637

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(b) Load flow result :

Load flow bus status (Loadflowbusstatus.txt)

Bus Voltage Angle ------Load------ ---Generation--- Injected

No. Mag. Degree MW Mvar MW Mvar Mvar

1 1.1000 0.0000 70.000 10.000 56.899 398.564 0.0002 0.9000 7.7121 45.000 10.000 100.000 -345.175 0.000

3 1.0000 2.5717 50.000 10.000 86.000 -15.715 0.000

4 1.0000 4.4050 30.000 10.000 130.000 79.937 0.000

5 1.0273 1.7730 35.000 10.000 0.000 0.000 0.000

6 0.9761 1.2120 100.000 10.000 0.000 0.000 0.000

Total 330.000 60.000 372.899 117.611 0.000

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Real Power Transmission Congestion Distribution factors (PTCDF) are asunder:

line no from to Real Power Distribution factor

________________________________________________

1 1 2 0.1904

2 1 5 -0.0037

3 2 4 0.3031

4 3 5 0.0815

5 3 6 -0.1026

6 4 5 -0.1509

7 4 6 -0.4593________________________________________________

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Weak bus Results are as under :

-----------------------------------------------

Load Bus dq/dv

-----------------------------------------------

5 0.02540466 0.0423613

-----------------------------------------------

Minimum dQ/dV is 0.0254 for bus no 5

Hence bus 5 is weak bus

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Reactive power injection from (1 to 50 Mvar) at weak bus for congestion management

Shunt: 1 -> Voltage(Kv) : 1.02679 -> ATC : 31.000 (MW)















Shunt: 16 -> Voltage(Kv) : 1.03074 -> ATC : 3.000 (MW)Shunt: 17 -> Voltage(Kv) : 1.03101 -> ATC : 3.000 (MW)


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Shunt: 20 -> Voltage(Kv) : 1.03179 -> ATC : 11.000 (MW)Shunt: 21 -> Voltage(Kv) : 1.03205 -> ATC : 15.000 (MW)Shunt: 22 -> Voltage(Kv) : 1.03232 -> ATC : 18.000 (MW)Shunt: 23 -> Voltage(Kv) : 1.03258 -> ATC : 22.000(MW)Shunt: 24 -> Voltage(Kv) : 1.03284 -> ATC : 25.000 (MW)Shunt: 25 -> Voltage(Kv) : 1.03310 -> ATC : 27.000 (MW)Shunt: 26 -> Voltage(Kv) : 1.03336 -> ATC : 31.000 (MW)Shunt: 27 -> voltage(Kv) : 1.03362 -> ATC : 32.000 (MW)

Shunt: 28 -> Voltage(Kv) : 1.03388 -> ATC : 34.000 (MW)Shunt: 29 -> Voltage(Kv) : 1.03414 -> ATC : 37.000 (MW)Shunt: 30 -> Voltage(Kv) : 1.03440 -> ATC : 37.000 (MW)Shunt: 31 -> Voltage(Kv) : 1.03466 -> ATC : 39.000(MW)Shunt: 32 -> Voltage(Kv) : 1.03492 -> ATC : 37.000 (MW)Shunt: 33 -> Voltage(Kv) : 1.03518 -> ATC : 36.000 (MW)Shunt: 34 -> Voltage(Kv) : 1.03544 -> ATC : 36.000 (MW)

Shunt: 35 -> Voltage(Kv) : 1.03570 -> ATC : 33.000 (MW)Shunt: 36 -> Voltage(Kv) : 1.03596 -> ATC : 32.000 (MW)Shunt: 37 -> Voltage(Kv) : 1.03622 -> ATC : 28.000(MW)Shunt: 38 -> Voltage(Kv) : 1.03648 -> ATC : 26.000 (MW)Shunt: 39 -> Voltage(Kv) : 1.03674 -> ATC : 20.000 (MW)


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Shunt: 41 -> Voltage(Kv) : 1.03726 -> ATC : 10.000 (MW)Shunt: 42 -> Voltage(Kv) : 1.03752 -> ATC : 4.000 (MW)Shunt: 43 -> Voltage(Kv) : 1.03777 -> ATC : 2.000 (MW)Shunt: 44 -> Voltage(Kv) : 1.03803 -> ATC : 9.000 (MW)Shunt: 45 -> Voltage(Kv) : 1.03829 -> ATC : 16.000 (MW)



Shunt: 48 -> Voltage(Kv) : 1.03906 -> ATC : 29.00 (MW)Shunt: 49 -> Voltage(Kv) : 1.03932 -> ATC : 21.00 (MW)


_________________________________________________________

Final ATC : 39.0000 (MW) at shunt :5.00 (Mvar) at bus no 5

_________________________________________________________

Program.txt
http://bhargav.txt/http://bhargav.txt/

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Result

1 2 3 4 5 6 7-0.4

-0.2

0

0.2

0.4Plot for distribution factor at given Line

Line No.

Distributionfactor

0 5 10 15 20 25 30 35 40 45 500

10

20

30

40

X: 5

Y: 39

Shunt MVar

ATC

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Conclusion & Future Scope

It conclude that ATC calculation is very important &mandatory for Open Access in power system inDeregulated Electrical Market .

In future with the help of some optimization techniqueslike genetic algorithm, Particle Swam Optimization, wecan optimized reactive power injection at weak bus.

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2. A.R Abhayankar,prof.S.A.Khaparde Introduction to deregulation in power industry.

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10. Sarika Kushalani, S.A Khaparde, S.A. Soman, Congestion management in the Emerging Energy

Market Structure,Cigre Regional Meeting on Bulk Power Transmission System Integration inDeveloping countries, pp-VII-16 to 24 New Delhi Nov.2001

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11. E.A Leonidaki, N.D.Hatziargyriou, G.A. Manos,A Systematic Approach for Effective Location ofSeries compensation to increased Available Transfer capabilityIEEE , Portio Power techConference , September 2001,Portugal.

12. N. Schnurr and W.H. Wellssow, Determination and Enhancement of the Available TransferCapability in FACTS.IEEE , Portio Power tech Conference , September 2001,Portugal.

13. Ashwani Kumar, S. C. Srivastav , Power Transaction Allocation in a Deregulated Market usingAC Power Transfer Distribution Factors Cigre Regional Meeting on Bulk Power TransmissionSystem Integration in Developing countries, pp-VIII-9 to 17 New Delhi Nov.2001

14. Chen-Ching Liu, Gerald T. Heydt, Abedal-Aty Edris, Impact of FACTS controller on Transfercapability of Power grid,IEEE, 2002, pp 556-261

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20. B.Mozafari, A.M.Rajbar, A.R. Shirani & A.Barkeseh,A comprehensive Method forATCcalculation in deregulated power systemIEEE International conference on Electric UtilityDeregulation , Restructuring & Power Technology April 2004 , pp 680 to 685.

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Enhancement Using RPF techniques,IEEE ,2004, pp 30-3523. Linzhong Yao, Phill Cartwright. Laurent Schimitt, Xiao-Ping Zhang, Congestion Management ofTransmission System Usin FACTSIEEE/PES transmission and Distribution conference andexhibition: Asia and Pacific Dalian, China, 2005

24. Naresh Acharya,N. Mithulananthan, Locating Series FACTS devices for congestion managementin deregulated electricity markets, Electric Power system Research 2332 (2006), pp 1-9.

25. A.S. Nayak and M.A. Pai Congestion management in Restructured Power system using an optimalPower flow Frame work, University of Illinois at Urbana-Champaign

26. K. Bhattacharya, M.H.J.Bollen, J.E.Dalder, Operation of restructured power system,Kulwar

Acadamic Publishers, Boston.27. Wood & Woolen breg , Power generation Operation & control

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No.2, pp 889-896, May 2004.

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28. Formation of Independent System Operator (ISO) Dr Sanjay GuptaSenior Consultant Energy & Utilities Group Infosys Technologies LimitedBangalore, India

29. N.G. Hingorani, Flexible A.C. transmission IEEE spectrum, April 1993, pp40-45

30. Abhijit chakravarti & Sunita Haldar Power system Analysis.

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Reference Websites

www.powerexindia.com

www.iexindia.com

www.pserc.cornell.edu/tcc

www.powergridindia.com www.nldc.in

www.erldc.org

www.wrldc.com

www.spp.org Atc_april2010_powergrid
http://www.powerexindia.com/http://www.powerexindia.com/http://www.powerexindia.com/http://www.powerexindia.com/http://www.powerexindia.com/http://www.iexindia.com/http://www.iexindia.com/http://www.iexindia.com/http://www.pserc.cornell.edu/tcchttp://www.pserc.cornell.edu/tcchttp://www.pserc.cornell.edu/tcchttp://www.powergridindia.com/http://www.powergridindia.com/http://www.powergridindia.com/http://www.nldc.in/http://www.erldc.org/http://www.wrldc.com/http://www.spp.org/http://atc_jan10.xls/http://atc_jan10.xls/http://www.spp.org/http://www.wrldc.com/http://www.erldc.org/http://www.nldc.in/http://www.powergridindia.com/http://www.powergridindia.com/http://www.powergridindia.com/http://www.pserc.cornell.edu/tcchttp://www.pserc.cornell.edu/tcchttp://www.pserc.cornell.edu/tcchttp://www.iexindia.com/http://www.iexindia.com/http://www.iexindia.com/http://www.powerexindia.com/http://www.powerexindia.com/http://www.powerexindia.com/http://www.powerexindia.com/http://www.powerexindia.com/

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Thank You

424 final

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