MVAR MANAGEMENT

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Reactive Power Management

- Case study

-- Nandan Pathak (AE)

ICT -1 ICT -2

220 kV

Girwali Bus

200 MW

160 MVAR

LOAD

200 MW

160 MVAR

G-3 G-4 G-5

160 MW

135 MVAR

160 MW

135 MVAR

160 MW

140 MVAR

220 kV Parli

Bus

LOAD

GENERATION

~

LOAD:

870 MW

730 MVAR

A ) GENERATORS: a) High MVAR drawl

B) ICT: b) High excitation current a) Overloading due to MVAR b) Low voltage on 220 kV bus ( 200 kV)

C) LOAD:

11 kV side: a) Overload tripping b) Very low voltages c) Conductor snapping d) Local load shedding

440 V side: a) Failure of transformers b) Conductor snapping

A) High seasonal load especially agriculture during October to March

B) Failure of reactive compensation

A) Identification of areas a) Beed district b) Solapur district c) Nanded district d) Pabhani district e) Latur district

A) Identification of radial feeders

220 kV

Girwali Bus

~ ~

220 kV Nanded

160 MW 100 MVAR

220 kV Parbhani

100 MW 80 MVAR

132 kV Parli

Bus

132 kV

Girwali Bus

132kV Beed

80 MW 60 MVAR

132 kV Latur -1

90 MW 75 MVAR

132 kV Latur -2

60 MW 45 MVAR

On similar lines loaded 11 & 33 feeders were identified.

I) Reactive power compensation available : i. Substation ----- 164 MVAR ii. Switched capacitors on 11kV – 240 MVAR (0.6 X405)

II) Focus Area – 11 kV , 0.6 MVAR capacitors a. Repairs in a central laboratory b. On site replacement, checking, modification, training

Modifications adopted for optimum compensation

1.

Cell rating 0.66 Mvar at 12 kV

2. De-rating at Low Voltage

3. Modification

A. Fixed capacitors

B. Addition to basic scheme

4. On site demonstrations

5. Team visit – Nasik , Pune (R ),

Kolhapur, Sangli,Parbhani

1. Reduction in overload tripping of 11 kV &

33 kV feeders.

2. Reduction in blowing of HG fuses at 33/11 kV transformers.

3. Reduction in conductor snapping.

4. Improvement in voltage profiles

LT 105 Volts to 190 volts

11kV 7.6 kV to 9.8 kV

ICT -1 ICT -2 G-3 G-4 G-5

220 kV

Girwali Bus

250 MW ( 200)

100 MVAR( 160 )

LOAD

250 MW (200)

100MVAR (160)

200 MW (160)

60 MVAR( 135 )

200 MW

60 MVAR

195 MW (150)

80 MVAR (140)

220 kV Parli

Bus

LOAD

GENERATION

~

Voltage changes:

220 kV

132 kV

33 kV

LOAD:

1095 MW (870)

400 MVAR (730)

215 kV (200 kV)

125 kV (106 kV)

31 kV (27 kV)

Radial load changes

132 kV

Girwali

Bus

132 kV Latur –1

105 MW 40 MVAR

(90 MW 75 MVAR)

132 kV Latur –2

70 MW 30 MVAR

(60 MW 45 MVAR)

~ ~

132kV Beed

95 MW 30 MVAR

(80 MW 60 MVAR)

132 kV

Parli Bus

KWH recorded on 11kV Matkuli feeder from 132 / 11 kV T/F at 132 kV Ashti substation

MONTH

January

February

March

April

May

June

July

August

September

October

November

December

KWH 1998

791500

545000

667900

539400

512000

164400*

313900

310400

330600

500300

530400

307300*

KWH 1999

1101100

938100

819800

790900

473200

459800

1170300 

948000 

630400

706100

854700

1104100

KWH 2000

1014800

699100

663300*

87400*

-*

167700*

442100

490900

342700

350100

626000

542000

•---Load shifted to another feeder  --- Load of other feeder taken on this feeder

•** --- kWh meter stopped due to leading PF

Note:

0.6 MVAR capacitor bank recommissioned at village Pandharee on Dt.28.11.2000

0.6 MVAR capacitor bank added at same location on Dt.4.12.2000

New 0.6 MVAR capacitor bank commissioned at Pokharni Phata on Dt.8.12.2000

KWH 2001

401700

239400

262200

183400

275400

43800**

1200000

1000000

800000

600000

400000

200000

0

Ja n u ar y

F eb ru ar y

M ar ch

A p ri l

M ay

Ju n e

Ju ly

A u g u st

S ep te m b er

O ct o b er

N o ve m b er

D ec em b er

1998

1999

2000

2001

Month

Energy savings on 11 kV Matkuli feeder

Forecasted Energy sent out (kWH)

Actual Energy sent out

(kWH)

Savings

(kWH)

Dec 2000 689997 542000 147997

Jan 2001

Feb 2001

Mar 2001

Apr 2001

May 2001

Total

624172

520905

562029

511766

451451

3360320

401700

239400

265200

183400

275400

1907100

222472

281505

296829

328366

176051

1453220

Remark

21.45 

35.60 

54.00 

52.00 

64.10 

39.00 

43.24 

1.System requires high order reactive compensation.

2.Use of fixed value non switched/seasonal manual switched capacitors is economical.

3. Complementary switching for optimum compensation.

4. Dedicated setup for overall line loss reduction.

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