Reactive Power Management - Case study -- Nandan Pathak (AE)

ICT -1 ICT -2G-3G-4G MW 160 MVAR 160 MW 135 MVAR 200 MW 160 MVAR 160 MW 135 MVAR 160 MW 140 MVAR LOAD 220 kV Girwali Bus 220 kV Parli Bus

~ GENERATION 870 MW 730 MVAR LOAD: A ) GENERATORS: a) High MVAR drawl b) High excitation current B) ICT: 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 132kV Beed 80 MW 60 MVAR ~ ~ 132 kV Latur MW 75 MVAR 132 kV Latur MW 45 MVAR 132 kV Girwali Bus On similar lines loaded 11 & 33 feeders were identified.

I) Reactive power compensation available : i. Substation 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 2. De-rating at Low Voltage 3. Modification 3. Modification A. Fixed capacitors A. Fixed capacitors B. Addition to basic scheme 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 LT 105 Volts to 190 volts 11kV7.6 kV to 9.8 kV 11kV7.6 kV to 9.8 kV

ICT -1 ICT -2G-3G-4G MW (200) 100 MVAR(160) 200 MW(160) 60 MVAR(135) 250 MW(200) 100MVAR(160) 200 MW 60 MVAR 195 MW(150) 80 MVAR(140) LOAD 220 kV Girwali Bus 220 kV Parli Bus

~ GENERATION 1095 MW (870) 400 MVAR (730) LOAD: Voltage changes: 220 kV 215 kV (200 kV) 132 kV 125 kV (106 kV) 33 kV 31 kV (27 kV)

Radial load changes 132 kV Parli Bus 132kV Beed 95 MW 30 MVAR (80 MW 60 MVAR) ~ ~ 132 kV Latur –1 105 MW 40 MVAR (90 MW 75 MVAR) 132 kV Latur –2 70 MW 30 MVAR (60 MW 45 MVAR) 132 kV Girwali Bus

MONTHKWH 1998KWH 1999KWH 2000KWH 2001 January February March * April * May * June164400* *43800** July  August  September October November December307300* 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 MVAR capacitor bank added at same location on Dt New 0.6 MVAR capacitor bank commissioned at Pokharni Phata on Dt KWH recorded on 11kV Matkuli feeder from 132 / 11 kV T/F at 132 kV Ashti substation

MonthForecasted Energy sent out (kWH) Actual Energy sent out (kWH) Savings (kWH) Remark Dec  Jan  Feb  Mar  Apr  May  Total  Energy savings on 11 kV Matkuli feeder

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.