Reactive Power Management

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Reactive Power Management - Case study
-- Nandan Pathak (AE)
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Preface
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Problem
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)
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Problem
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
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Analysis

• High seasonal load especially agriculture
• during October to March
• B) Failure of reactive compensation

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Analysis

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

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Analysis

1. Identification of radial feeders

On similar lines loaded 11 33 feeders were
identified.
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Action
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
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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

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Modified 1.2 MVAR version
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Modified 1.2 MVAR version
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Action

• 4. On site demonstrations
• 5. Team visit Nasik , Pune (R ), Kolhapur,
  Sangli,Parbhani

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Observations

• 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

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Changed System scenario
ICT -2
G-3
G-4
G-5
ICT -1
200 MW(160) 60 MVAR(135)
195 MW(150) 80 MVAR(140)
200 MW 60 MVAR
250 MW(200) 100MVAR(160)
250 MW (200) 100 MVAR(160)
220 kV Parli Bus
220 kV Girwali Bus
LOAD
LOAD
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Changed System scenario
Voltage changes 220 kV 215 kV (200 kV)
132 kV 125 kV (106 kV) 33 kV 31 kV
(27 kV)
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Changed System scenario
Radial load changes
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KWH recorded on 11kV Matkuli feeder from 132 /
11 kV T/F at 132 kV Ashti substation

• ---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

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Changed System scenario
Energy savings on 11 kV Matkuli feeder
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Conclusion
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.