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					Reactive Power Management
       - Case study


            -- Nandan Pathak (AE)
  ICT -1                 ICT -2          G-3        G-4       G-5



                                               160 MW     160 MW        160 MW
              200 MW          200 MW           135 MVAR                 140 MVAR
                                                          135 MVAR
              160 MVAR        160 MVAR
                                                                     220 kV Parli
220 kV                                                               Bus
Girwali Bus



              LOAD                                 LOAD
 GENERATION         LOAD:


    ~
                        870 MW

                         730 MVAR


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     220 kV Parbhani
              160 MW 100 MVAR   100 MW 80 MVAR                    132 kV Parli
                                                                  Bus


                                                  132kV Beed
132 kV                                            80 MW 60 MVAR
Girwali Bus


              132 kV Latur -1   132 kV Latur -2
              90 MW 75 MVAR     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



                                                   200 MW(160) 200 MW        195 MW(150)
              250 MW (200)    250 MW(200)          60 MVAR(135) 60 MVAR      80 MVAR(140)
              100 MVAR(160)   100MVAR(160)
                                                                          220 kV Parli
220 kV                                                                    Bus
Girwali Bus



              LOAD                                     LOAD
   GENERATION      LOAD:


      ~
                       1095 MW (870)

                       400 MVAR (730)

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
                                            ~        ~
Girwali
Bus                                                       132 kV
          132 kV Latur –1 132 kV Latur –2                 Parli Bus
          105 MW 40 MVAR 70 MW 30 MVAR
          (90 MW 75 MVAR) (60 MW 45 MVAR)   132kV Beed
                                            95 MW 30 MVAR
                                            (80 MW 60 MVAR)
   KWH recorded on 11kV Matkuli feeder from 132 / 11 kV T/F at 132 kV Ashti substation


   MONTH             KWH 1998           KWH 1999           KWH 2000            KWH 2001
   January               791500            1101100            1014800              401700
   February              545000             938100             699100              239400
    March                667900             819800            663300*              262200
     April               539400             790900             87400*              183400
     May                 512000             473200                 -*              275400
     June               164400*             459800            167700*             43800**
     July                313900           1170300             442100
    August               310400            948000             490900
  September              330600             630400             342700
   October               500300             706100             350100
  November               530400             854700             626000
  December              307300*            1104100             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
     Ja




                         200000
                                   400000
                                               600000
                                                          800000
                                                                   1000000
                                                                             1200000




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           r
                                  2001
                                            2000
                                                   1999
                                                            1998
        Energy savings on 11 kV Matkuli feeder
Month        Forecasted Energy sent   Actual Energy sent out   Savings     Remark
             out (kWH)                (kWH)                    (kWH)


Dec 2000            689997                   542000              147997    21.45 


Jan 2001            624172                   401700              222472    35.60 


Feb 2001            520905                   239400              281505    54.00 


Mar 2001            562029                   265200              296829    52.00 


Apr 2001            511766                   183400              328366    64.10 


May 2001            451451                   275400              176051    39.00 


Total               3360320                  1907100             1453220   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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