green practices in electrical system - ciigbc© confederation of indian industry electrical system...

© Confederation of Indian Industry

Green Practices In Electrical System


Electrical System

vEnergy efficiency measures will add $505

billion to India’s gross domestic product

(GDP) between 2009 and 2017

vImmense energy efficiency potential

possible

vAround 2500 MW of energy savings

possible only in electrical system


Electrical System

GENERATOR

TRANSFORMER

LOAD

DISTRIBUTION


THANK YOU

1


Generators


Improving Power Factor Of Generator

vCan generator be operated in higher power factor than the design value?ØYES

vUsually designed for 0.80 PF lag as specified by standards

vLower power factor demands higher excitation currents and results in increased losses

2


Alternator Capability Curve

Source: Cummins Power



vHigher power factor

ØLower excitation current

ØHigher alternator efficiency

ØHigher generation due to higher efficiency

vAt the least, 0.4% efficiency improvement

possible by improving PF from 0.8 to Unity

3



vTGs rated forØ30 MW & 37.50 MVA

vOperating at 0.80 PF

96.9196.03%25% Load98.1897.59%50% Load98.597.98%75% Load98.5698.08%100 % Load0.990.8Efficiency @ P.F


vImproved PF in steps

ØEfficiency improved by 0.59%

vAction Taken:

ØImproved power factor from 0.80 to 0.99 in steps

vReduced the excitation slowly

ØInstalled additional capacitor banks to meet

kVAR requirement


4



Annual Saving - Rs 35.0 Lakhs

Investment - Rs 38.0 Lakhs

Simple Payback - 14 Months


Transformers


TransformervIndustries are the not the only one

which has transformersØA Cell phone chargers also does


TransformervA quick calculationØTotal mobile phones in India = 300 million

(According to IDC reports)

ØAssuming 10% of people are habitual of leaving chargers on = 30 million

ØAssuming the charger is left on for 10 hrs for 365 days a year


TransformervA quick calculationØCharger consumes 0.5 W power

ØEnergy Loss per year = 55000 MWhvAccording to NokiaØ switching off cell phone charges can save

power equivalent to power consumed in 66,000 European homes


Transformer Efficiency

vEnergy Efficiency in transformer system

ØTechnology up gradation

ØFine Tuning of system

vTechnology up gradation

ØAmorphorous Transformers

vFine Tuning of System

ØTransformer Loss Calculation


Transformer Efficiency

Iron losses

Copper losses


Transformer Loss Calculation

132 KV Breaker

50 MVA11 KV / 132KV

80% Loaded

50 MVA11 KV / 132KV

No Load

Bus Coupler


Transformer Loss CalculationvLosses – from test certificateØIron loss = 25 kW

ØFL. Copper losses = 225 kW

Loss calculation

vOne transformer in operation

(25) + 225 x (0.80) 2 = 169 kW

vAdditional loss in stand by transformerØ25 kW – Iron loss


Transformer Loss Calculation132 KV Breaker

50 MVA11 KV / 132KV

40% Loaded

50 MVA11 KV / 132KV

40% Loaded

Bus Coupler


Transformer Loss CalculationvBoth transformers in operation

[(25) + 225 x (0.40) 2 ] x 2 = 122 kW

vReduction in loss : 72 kW


Investment - Nil

1


Distribution


Distribution Loss – Case Study

vTotal technical & commercial loss in TN

Ø 2011 – 12 > Rs 60,000 Crores

ØNext five years> Rs 1,00,000 Crores

vPunjab State Electricity Board’s (PSEB)

transmission and distribution loss

Ø25%

qDecided to reduce losses

2


Distribution Loss – Case StudyvReplaced the existing 3-phase 400V Low

Voltage Distribution System feeding Agricultural Pumps, with an 11-kV High Voltage Distribution System (HVDS)vBenefits of the projectØReduction in transmission lossesØEnergy saved could be used by additional

consumersØImproved voltage profile to consumersØReduction in failure of transformers due to over

loading


Distribution – A Case Study

6 MW

11kV

11kV11kV

Plant A Load

Plant B load

415V415V

415V

1000kVA 1000kVA 1000kVA2500kVA 2500kVA

Tr -2

Tr -3

Plant A Plant B

3


Distribution – A Case Studyv11 kV feeder of Plant A – Not in operationØCable Failure

vLoad of Plant A catered by Transformer 2 of Plant BvThree level voltage transformation usedØLT – HT – LT

vEach voltage transformation has its own efficiency ØHigher no. of transformations, higher the

lossesØInherent losses of transformers


Distribution – A Case Study

vAction Taken:ØLoad of Plant A directly connected to

secondary of Transformer 2 of Plant BqInstalled bus coupler and separate breakers at the

secondary of Plant A distribution transformers

ØSwitched off Plant A transformers

Annual Saving - Rs 7.00 LakhsInvestment - Rs 21.00 LakhsPayback period - 36 Months

4


Voltage Dropv Voltage drop is an indication of distribution

loss

v Causes of voltage dropØ Poor power factor

Ø Inadequate cable size laid

Ø Poor contact surface atq Cable Termination

q Cable joints

q Contactors/Switches


Voltage Drop

v In a large complex distribution system,

voltage drops are very common

v Acceptable limit in a 3 Ph. System is

4-5 Volts / Phase

vMore than 5 V/Phase indicates energy

loss in the distribution

5


Case Study-Voltage Dropsv Voltage drop – PCC to MCC

Measurements

q Voltage at PCC = 418 V

q Voltage at MCC = 405 V

q Drop in Voltage = 13 Volts

q Load current = 225 A

q Power factor = 0.6 Lag

q Cable size = 1R x 3C x 300 Sq.mm


Case Study-Voltage Drops

v Cable loss = 5.1 kW

v Capacitor installed at Load end = 60 kVAr

v Reduction cable loss = 2.5 kW

Annual savings= 0.76 Lakhs

1


LoadsMotor - Lighting


Operation of VFD

vVFDs not an universal remedy for energy

efficiency

vVFDs also has efficiency

Ø~96 - 98% efficient

vAt full speed, no energy saving

vEnergy loss operating VFD @ 50 Hz

Ø2% to 2.5 %

2


Operation of VFD

vA plant operated 20 VFDs at full speed

vAction taken

ØBypassed VFDs at full speed


Investment - Nil


Motor Efficiency

vEnergy Efficiency in Motors

ØTechnology up gradation

ØFine Tuning of system

vTechnology up gradationØEnergy Efficient motors

vFine Tuning of System

3


System Fine Tuning


Power = √3 V I Cos φ

Cos φ is power factor

Capacity α Torque

α Voltage 2

Basic Formulae

4


Optimization Of Lightly Loaded Motorsv OptionsØ Delta connection to permanent star connection -Steady load applicationØ Automatic star-delta-star converters- for

variable loadsØ Soft starter cum energy savers - High Starting torque applicationsØ Variable voltage devicesØ Down sizingØ Overall voltage optimization


v Impact on motor operating parameters

ØReduction in voltage dependent losses - Drop in

Magnetization current

ØCapacity reduces

ØPF improves

ØLoad current drops

ØLoad factor improves

ØEfficiency Improves

Capacity α Voltage 2

5


Automatic Star-delta-starv Principle of Voltage optimizationv Starting torque problems

ØStarting equipment on loadv Now available with DOL changer switch

for starting purpose

Energy Saving Protection

% LStar Mode (Low Load) (High Load) ∆ Mode

Load Sensor


Automatic Star Delta Star Starters for Belt Conveyors

v Most of the time lightly loadedv Subject to heavy loadØ Rated KW = 90.0KW(3 nos)Ø Actual load = 35.0 KWØ In star mode consumes = 32.0 KWØ Savings in KW = 9.0 KW

Annual savings - Rs 2.8 LakhsInvestment - Rs 1.2 LakhsPayback period - 5 months

6


Optimise operating frequency A Case study from a Cement Plant

vHas captive power plant – 45 MW

ØOperated in island mode

ØOperating frequency : 50 Hz

vStudied all major equipment

ØCapacity utilisation : 60 – 80%


Optimise operating frequency vReduced the overall frequency to 49 Hz in

steps of 0.2 Hz ØObserved the operating parametersØNo effect on productionØFound reduction in energy consumption


7


Lighting System Efficiency Improvement

vImproving Lighting System Efficiency ØTechnology up gradationØFine Tuning of system

vTechnology up gradationØUsage of higher efficacy lampsØEnergy efficiency LED lampsØLight pipesØOptical fibre

vFine Tuning of SystemØVoltage optimisation


Technology Up Gradation

8


Latest Technologies – Light Pipe


Latest Technologies – Light Pipe

9


Latest Technologies – Fibre OpticsvFibre OpticsØPopular in medical fieldqUsed for lighting in operation theatres

ØSame concept applicable for other applications

vFibre optics in combination with solar PV –an excellent choice


Latest Technologies – Fibre Optics

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