Download - REVISION OF SCHEDULES/REQUISITIONS
REVISION OF SCHEDULES/REQUISITIONS
A) OUTAGE OF GENERATING UNITB) REVISED DECLARATION OF AVAILABILITY BY ISGSC) OUTAGE OF A TRANSMISSION ELEMENTD) UNFORESEEN LOAD-CREASH
TAKES EFFECT FROM
A) 4TH TIME BLOCK IN CASE OF- FORCED OUTAGE OF A GENERATING UNIT- TRANSMISSION CONSTRAINT- GRID DISTURBANCE- SUO MOTO BY RLDC
B) 6TH TIME BLOCK IN CASE OF- REVISION OF DECLARED AVAILABILITY BY ISGS
WHAT ALL CAN HAPPEN?
What all can happen on the day of Operation?
Prospective revision (upward / downward) of ISGS
availability (advised by ISGS through RLDC)
Schedules revision for remaining part of the day
TRIPPING OF ISGS UNIT
TRIPPING OF THE SEB’S UNITS
LOAD CRASH IN THE STATE
FREQUENCY IS GOOD OR HIGHFREQUENCY IS GOOD OR HIGH THE STATE IS OVERDRAWING
THE STATE IS UNDERDRAWINGTHE ISGS IS OVER GENERATINGTHE ISGS IS UNDER GENERATING
FREQUENCY IS LOWFREQUENCY IS LOW
THE STATE IS OVERDRAWING
THE STATE IS UNDER-DRAWING
THE ISGS IS UNDER GENERATING
THE ISGS IS OVER GENERATING
What all can happen on the day of Operation?What all can happen on the day of Operation?
What all can happen on the day of Operation?
TRIPPING OF ISGS UNIT (Known after the event)
Immediate frequency dip
All operating units pick up extra MW, SEB’s drawal reduces
SEBs get UI payment
After the transients : An SEB has the option of adjusting his
generation/load to increase/decrease his net drawal to forgo or
take advantage of UI, till ISGS revises availability and new
schedules come into effect.
What all can happen on the day of Operation? TRIPPING OF THE SEB’S OWN GENERATING UNITS
SEB’s net drawal from the grid increases
SEB has to pay UI
OPTIONSOPTIONS
1. Continue to overdraw and pay UI2. Carry out corresponding load shedding3. Run up all available generation4. Increase ISGS requisition, in case it was not fully requisitioned earlier
5. Enter into a bilateral with another SEB/ISGS for any idling capacity
What all can happen on the day of Operation?
LOAD CRASH IN THE STATE
Under-drawal from the grid and frequency rise
UI implicationsOPTIONSOPTIONS
1. Reduce own generation
2. Reduce ISGS requisition (only if frequency rises/is likely to rise so much that UI price falls below ISGS energy rate
3.Continue to under-draw, in effect supplying UI to the grid. This is advantageous as long as the frequency remains below about 50.2 Hz.
FREQUENCY IS GOOD OR HIGH AND THE STATE IS OVERDRAWING
No problem and no action required
Enhance optimisation, however to the extent possible
1. Reduce own generation to the extent possible, if frequency is above 49.8Hz and increase over-drawal
2. Restore consumer load that had been shed, provided tariff /realisation rate is higher than current UI rate. ( This is also increses overdrawal)
3. Increase ISGS requisition if some part of the entitlement had not been requisition earlier, provided the frequency is ( and is likely to remain) below 50.2Hz. (This would increase the drawal schedule and thereby reduce overdrawal)
FREQUENCY IS GOOD OR HIGH AND THE STATE IS UNDERDRAWING
Action required
1. Reduce own generation to the extent possible, if the frequency is above abiut 49.8 Hz(This would reduce under drawal)
2. Restore consumer load that had been shed, and reduce underdrawal
3. Reduce ISGS requisition, provided the previous two actions have been taken and the frequency continues to be above 50.2 – 50.3 Hz. If frequency is likely to remain below 50.2 Hz, bilateral sell to a needy neighbour can be tried.
FREQUENCY IS LOW AND THE STATE IS OVERDRAWING
Action required
1. Increase own generation to the maximum possible extent
2. Curtail customer load. Load shedding to be graded balancing between UI price and consumer category.
3. Increase ISGS requisition to full entitlement (If not requisitioned fully earlier), and arrange for bilateral purchase from another SEB/ ISGS
FREQUENCY IS LOW AND THE STATE IS UNDER-DRAWING
1. Increase own generation to the extent possible, provided the frequency is below about 49.5 Hz (Comparing variable cost with current UI price)
As such no action required. However the following can be done for enhanced optimisation
2. Curtail consumer load, by shedding low priority load (provided UI earning for the SEB justifies such load shedding). This is totally optional, and helps the grid.
3. Increase ISGS requisition to full entitlement (if not requisitioned fully earlier) and earn UI. Alternately sell the surplus through a bilateral agreement.
OPTIONS OF ISGS TO EVENTSWHAT ALL CAN HAPPEN ON THE DAY OF OPERATION ?
1. PROSPECTIVE REVISION OF DRAWAL REQUISITION BY A BENEFICIARY ( UPWARD / DOWNWARD)
• SCHEDULE REVISED FOR REMAIING PART OF THE DAY BY RLDC
2. TRIPPING OF A GENERATING UNIT OF A STATE (KNOWN AFTER THE EVENT).
• IMMEDIATE FREQUENCY DIP
• ALL OPERATING UNITS PICK UP EXTRA MW,
• ALL STATIONS INJECTION INCREASES
ISGS RECEVIES UI PAYMENT
OPTIONS OF ISGS :i. GENERATE AS PER SCH. AND FOREGO ADVANTAGE OF UI
ii. INCREASE NET INJECTION BY
• INCREAING OWN GENERATION
RECEIVE UI PAYMENT TILL THE BENEFICIARIES REVISE THEIR REQUISITIONS AND NEW SCHEDULES COME INTO EFFECT OR REDUCE THEIR DRAWALS
3. TRIPPING OF THE OWN GENERATING UNIT OF ISGS
• NET INJECTION OF ISGS REDUCES
STATION HAS TO PAY UI.
OPTIONS OF ISGS :
i. CONTINUE TO UNDER GENERATE AND PAY UI.
ii. INCREASE NET INJECTION BY
RUNNING UP ALL AVAILABLE GENERATION.Contd….
MINIMISE UI PAYMENT
iii) REVISE AVAILABILITY DECLARATION WHILE CONTINUING TO UNDER GENERATE (AND PAY UI) TILL REVISED SCHEDULES TAKE EFFECT.
iv) ENTER INTO A BILATERAL AGREEMENT WITH OTHER SEB/ISGS TO SUPPLY ANY SURPLUS/ IDLING CAPACITY.
4. LOAD CRASH IN A STATE:
• FREQUENCY INCREASES
• ISGS INJECTION REDUCES
UI IMPLICATION (NET GAIN/LOSS).
OPTIONS OF ISGS :
(i) REDUCE INJECTION BY
• REDUCING OWN GENERATION. (IF SYSTEM FREQUENCY IS HIGHER THAN THE STATIONS THRESHOLD FREQUENCY)
CONTINUE TO UNDER-INJECT, IN EFFECT SUPPLYING UI TO THE GRID. THIS IS ADVANTAGEOUS AS LONG AS THE SYSTEM FREQUENCY IS HIGHER THAN THE STATION’S THRESHOLD FREQUENCY
(ii) CONTINUE TO GENERATE AS PER SCHEDULE THUS AVOID ANY UI IMPLICATION TILL THE BENEFICIARIES REVISE THEIR REQUISITION AND REVISED SCHEDULES ARE ISSUED BY RLDC.
(iii) ENTER INTO A BILATERAL AGREEMENT WITH OTHER SEB/REGION TO SUPPLY SURPLUS /IDLING CAPACITY
FREQUENCY IS GOOD OR HIGH
THE ISGS IS OVER GENERATING
THE ISGS IS UNDER GENERATING
FREQUENCY IS LOW
THE ISGS IS UNDER GENERATING
THE ISGS IS OVER GENERATING
What all can happen on the day of Operation?What all can happen on the day of Operation?
FOUR SCENARIOS
A) FREQUENCY IS GOOD OR HIGH, AND THE ISGS IS UNDER GENERATING
OPTIONS OF ISGS:
i) INCREASE GENERATION IF THE SYSTEM FREQUENCY IS BELOW THE STATION’S THRESHOLD FREQUENCY.
ii) REDUCE OWN GENERATION TO THE EXTENT POSSIBLE AND THUS REDUCES NET INJECTION SO LONG AS FREQUENCY IS ABOVE THE
STATION’S THRESHOLD FREQUENCY.
iii) GENERATE AS PER SCHEDULE (NO UI IMPLICATION)
FOUR SCENARIOS
B. FREQUENCY IS GOOD OR HIGH, AND THE ISGS IS OVER GENERATING
OPTIONS OF ISGS :
i) REDUCE OWN GENERATION TO THE EXTENT POSSIBLE, IF THE FREQUENCY IS ABOVE THE STATIONS THRESHOLD FREQUENCY.
ii) INCREASE GENERATION IF FREQUENCY IS BELOW THE STATION’S THRESHOLD FREQUENCY
iii) GENERATE AS PER SCHEDULE (NO UI IMPLICATION)
C) FREQUENCY IS LOW, AND THE STATION IS UNDER GENERATING
OPTIONS OF ISGS :
i) INCREASE OWN GENERATION TO THE MAXIMUM POSSIBLE EXTENT AS LONG AS THE FREQUENCY IS BELOW THE STATION’S THRESHOLD FREQUENCY (THUS RECEIVE UI).
ii) GENERATE AS PER SCHEDULE – NO UI IMPLICATION.
FOUR SCENARIOS
D. FREQUENCY IS LOW, AND THE ISGS IS OVER GENERATING
• NO ACTION REQUIRED
FOLLOWING CAN BE DONE FOR ENHANCED OPTIMIZATION.
1. INCREASE OWN GENERATION TO THE EXTENT POSSIBLE, PROVIDED THE FREQUENCY IS BELOW THE STATION’S
THRESHOLD FREQUENCY. (THUS RECEIVE UI)
2. GENERATE AS PER SCHEDULE – NO UI IMPLICATION.
ACTION DEPENDS ON PREVAILING FREQUENCY, THE STATION’S THRESHOLD FREQUENCY AND IS INDEPENDENT OF WHETHER OVER-GENERATING OR UNDER-GENERATING. IT FOLLOWS THAT ON-LINE MEASUREMENT AND DISPLAY OF TELEMETERED DATA IS NOT ALL THAT CRITICAL
UNSCHEDULED INTERCHANGES (UI)UNSCHEDULED INTERCHANGES (UI)
i.e. deviation from schedules
ENCOURAGE if good for the grid, DISCOURAGE if bad for the grid but allows because it enables meeting more demand and enhances merit order
Good UI helps in improving frequency, and enables one constituent to help the other (for meeting more consumer demand i.e. reducing load shedding)
UI provide the mechanism for on line displacement of costlier generation by cheaper generation: ULTIMATE OPTIMISATION
ACTION DEPENDS ON PREVAILING
FREQUENCY, AND IS INDEPENDENT
OF WHETHER OVER-DRAWING OR
UNDER-DRAWING. IT FOLLOWS
THAT ON LINE MEASUREMENT AND
DISPLAY OF CORRECT NET DRAWAL
IS NOT ALL THAT CRITICAL.
UI = x – Scheduled Drawal
G L
X
IMPORT
X = L - G
0500
10001500200025003000350040004500500055006000
1 2 3 4 5 6 7 8 910111213141516171819202122232446.50
47.00
47.50
48.00
48.50
49.00
49.50
50.00
50.50AP DRAWAL ON A TYPICAL DAY 12.12.2001
0500
10001500200025003000350040004500500055006000
1 3 5 7 9 11 13 15 17 19 21 2347.50
48.50
49.50
50.50
51.50
52.50AP DRAWAL ON A TYPICAL DAY 12.12.2001
GENERATING STATIONINSTALLED CAPACITY IN
MW
ANDHRA PRADESH's SHARE(%)
PEAK
EX-PP CAPABILITY
ON 12/12/2001PEAK
ANDHRA PRADESH'S
ENTITLEMENT IN MWPEAK
ENERGY CHARGE IN
P/KwhTHRESHOLD FREQ (HZ)
NTPC,RAMAGUNDAM 2100 34.072 1923 655 86.22 50.19NLY-II STG1,NEYVELI 660 19.456 515 100 114.62 50.09NLY-II STG2,NEYVELI 870 25.419 517 131 165.22 49.91
MADRAS ATOMIC POWER STATION 340 9.753 290 28 57.49 50.29
KAIGA ATOMIC POWER STATION 440 31.667 380 120 310 49.39
TOTAL COST ASSUMED AS VARIABLE BECAUSE SINGLE COST SPECIFIED.AP'S OWN GENERATION
VIJ AYAWADA.T.P.S 1260 100 1061 1061 102.8 50.13KOTHAGUDEM T.P.S 670 100 474 474 123.1 50.06
KOTHAGUDEM T.P.S-V 500 100 252 252 102.1 50.14RAYALASEEMA T.P.S 420 100 441 441 124.5 50.06
NELLORE T.P.S 30 100 26 26 233.8 49.67VIZAG STEEL PLANT CAPTIVE 100 60 60 196 49.80
NAVBHARAT CAPTIVE 100 20 20 208 49.76GVK,J EGURUPADU 216 100 210 210 83 50.20
SPECTRUM 208 100 190 190 83 50.20VIJ J ESWARAM GTS-1 100 100 101 101 86 50.19VIJ J ESWARAM GTS-1I 172.5 100 171 171 87 50.19LANCO,KONDAPALLI 350 100 320 320 91.5 50.17
SRISAILAM 770 100 524 524N'SAGAR 810 100 270 270L.SILERU 460 100 300 300U.SILERU 240 100 170 170
TOTAL COST ASSUMED AS VARIABLE BECAUSE SINGLE COST SPECIFIED.*Hydel units are subject to annual schedules.
AVAILABILITY OF ANDHRA PRADESH:-TYPICAL DATA ON 12/12/2001
NIL* NA
SCHEDULING FOR KARNATAKA(ACTUAL) ON 04-01-02
0100200300400500600700800900
10001100120013001400150016001700180019002000210022002300240025002600270028002900300031003200330034003500360037003800390040004100420043004400
1 3 5 7 9 11 13 15 17 19 21 23HOUR
MW
CGS ENTITLEMENTS INCLUDING ER = 854 MW
THERMAL+DIESEL
IPP
HYDRO
DEMAND
24.3 MU
SCHEDULING FOR KARNATAKA (EXPECTED) ON 04-01-02
0100200300400500600700800900100011001200130014001500160017001800190020002100220023002400250026002700280029003000310032003300340035003600370038003900400041004200430044004500460047004800
1 3 5 7 9 11 13 15 17 19 21 23HOUR
MW
CGS ENTITLEMENTS INCLUDING ER = 854 MW
THERMAL+DIESEL
IPP
HYDRO
DEMAND
24.3 MU
GENERATING STATIONINSTALLED CAPACITY
IN MWKARNATAKA'S
SHARE(%)PEAK
EX-PP CAPABILITY
ON 04/01/2002
PEAK
KARNATAKA'S ENTITLEMENT IN
MWPEAK
ENERGY CHARGE IN P/Kwh
THRESHOLD FREQ (HZ)
NTPC,RAMAGUNDAM 2100 19.554 1923 376 37.66 50.37NLY-II STG1,NEYVELI 580 24.649 515 127NLY-II STG2,NEYVELI 790 24.379 512 125
MADRAS ATOMIC POWER STATION 340 7.234 130 9KAIGA ATOMIC POWER STATION 440 28.401 410 116
EASTERN REGION 500 21.2 475 101TOTAL GENERATION 4750 3965 854
AFTER APPORTIONING LOSS OF 2.86% 830KARNATAKA'S OWN GENERATION
RAICHUR THERMAL 1260 100 967 967YELAHANKA DIESEL 128 100 108 108
THERMAL TOTAL 1388 1075 1075SHARAVATHY 1035 100 869 869
LINGANAMAKKI 55 100 20 20GERSOPPA 180 100 0 0NAGJHARI 840 100 520 520
SUPA 100 100 45 45KADRA 150 100 94 94
KODASALLI 120 100 80 80VARAHI 230 100 165 165MANI 9 100 0 0
GHATAPRABHA 32 100 19 19BHADRA 39.2 100 9 9
SHIVA 42 100 0 0SHIMSHA 17.2 100 7 7
MUNIRABAD 27 100 15 15MAHATMA GANDHI 120 100 30 30
HYDRO TOTAL 2996 100 1873 1873
JINDAL IPP 260 100 120 120
THANEERBHAVI NAPTHA 230 100 211 211
TATA DIESEL 81 100 64 64
RAYALASEEMA 27 100 26 26IPP TOTAL 598 421 421
TOTAL GENERATION 4982 3369 3369
AVAILABILITY OF KARNATAKA:-TYPICAL DATA ON 04/01/2002
SCHEDULING FOR KERALA
0100200300400500600700800900
100011001200130014001500160017001800190020002100220023002400
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24HOURS
MW
NLY-II STG1 57 MWNLY-II STG2 60 MW
ER 74 MW
KAYAMKULAM 150 MW
KAPS 38 MW
NTPC 238 MW
MAPS 7 MW
IPP&DIESEL 119 MW
SCHEDULING FOR KERALA
0100200300400500600700800900
100011001200130014001500160017001800190020002100220023002400
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24HOURS
MW
KAYAMKULAM 150 MW
IPP&DIESEL 119 MW
CGS ENTITLEMENTS INCL ER 474 MW
HYPOTHETICAL 04.01.2002
GENERATING STATIO N INSTALLED KERALA'S EX-PP KERALA'S ENERGY THRESHOLD NTPC,RAMAGUNDAM 2100 12.112 1923 233 86.22 50.19NLY-II STG1,NEYVELI 660 11.132 515 57 114.62NLY-II STG2,NEYVELI 870 11.651 512 60 165.22
MADRAS ATOMIC POWER STATION 340 5.445 130 7 57.49KAIGA ATOMIC POWER STATION 440 9.187 410 38 310
EASTERN REGION 500 19.6 475 93TO TAL 4910 3965 488
KERALA OWN GENERATIO NKUTTIADI + EXTN 125 100 115 115
SHOLAYAR 54 100 36 36PORINGAL+BANK 48 100 40 40
PALLIVASAL 37.5 100 13 13SENGULAM 48 100 24 24PANNIAR 30 100 16 16
NERIMANGALAM 45 100 45 45SABARIGIRI 300 100 300 300
IDUKKI 780 100 590 590IDAMALAYAR 75 100 35 35
KALLADA 15 100 6 6L.PERIYAR 180 100 146 146KAKKAD 50 100 38 38
MINI HYDRO 26.5 100 13 13HYDRO TO TAL 1814 100 1417 1417
BRAHMAPURAM DIESEL 106.5 100 18 18KOZHIKODE DIESEL 128.8 100 88 88
KAYAMKULAM 350 100 156 156BSES GAS 130.5 100 0 0
KASARGODE POWER 21.93 100 20 20THERMAL TO TAL 738 100 282 282
TO TAL GENERATIO N 2552 100 1700 1700
AVAILABILITY O F KERALA:-TYPICAL DATA O N 04/01/2002
TOTAL COST AS SINGLE COST SPECIFIED.
SCHEDULING FOR TAMILNADU(ACTUAL)
-300-200-1000100200300400500600700800900100011001200130014001500160017001800190020002100220023002400250026002700280029003000310032003300340035003600370038003900400041004200430044004500460047004800490050005100520053005400550056005700580059006000610062006300
1 3 5 7 9 11 13 15 17 19 21 23HOUR
MW
THERMAL+DIESEL+GAS
IPP
HYDRO
DEMAND
CGS ENTITLEMENTS INCLUDING ER:1118 MW
KADAMPARAI IN PUMP MODE
04.01.2002
SCHEDULING FOR TAMILNADU(EXPECTED)
-300-200-100010020030040050060070080090010001100120013001400150016001700180019002000210022002300240025002600270028002900300031003200330034003500360037003800390040004100420043004400450046004700480049005000510052005300540055005600570058005900600061006200630064006500
1 3 5 7 9 11 13 15 17 19 21 23HOUR
MW
THERMAL+DIESEL+GAS
IPP
HYDRO
DEMAND
CGS ENTITLEMENTS INCLUDING ER:1118 MW
KADAMPARAI IN PUMP MODE
04.01.2002
GENERATING STATIONINSTALLED CAPACITY
IN MW
TAMIL NADU'S
SHARE(%)PEAK
EX-PP CAPABILITY
ON 04/01/2002
PEAK
TAMIL NADU'S ENTITLEMENT
IN MWPEAK
ENERGY CHARGE IN P/Kwh
THRESHOLD FREQ (HZ)
NTPC,RAMAGUNDAM 2100 25.506 1923 490 91.48 50.17NLY-II STG1,NEYVELI 580 32.239 515 166NLY-II STG2,NEYVELI 790 35.379 512 181
MADRAS ATOMIC POWER STATION 340 76.058 130 99KAIGA ATOMIC POWER STATION 440 27.719 410 114
EASTERN REGION 500 21.2 475 101TOTAL GENERATION 4750 3965 1151
1118TAMIL NADU'S OWN GENERATION
Ennore TPS 450 100 134 134 203.36 49.77North Chennai TPS 630 100 644 644 142 49.99
Tuticorin TPS 1050 100 870 870 144 49.99Mettur TPS 840 100 850 850 142 49.99Neyveli TS1 600 100 398 398Basin Bridge 120 100 52.4 52.4 489 48.75
Kovil kalappal 105 100 90 90THERMAL+ GAS TOTAL 3795 3038 3038
Pykara 72 100 48.6 48.6Moyar 36 100 22 22
Parsonsvalley 30 100 0 0Kundah - 1 60 100 24 24Kundah - 2 175 100 50 50Kundah - 3 180 100 82 82Kundah - 4 100 100 63 63Kundah - 5 40 100 0 0Kadamparai 400 100 388 388
Aliyar 60 100 58 58Mettur Dam 40 100 10.4 10.4
Mettur Tunnel 200 100 56 56LMHEP-Barrage-1 30 100 15.8 15.8LMHEP-Barrage-2 30 100 15 15LMHEP-Barrage-3 30 100 15 15LMHEP-Barrage-4 30 100 12.6 12.6
Periyar 140 100 58 58Servalar 20 100 16.8 16.8
Papanasam 28 100 20.2 20.2Sarkarpathy 30 100 27.2 27.2Sholayar-1 70 100 31.2 31.2Sholayar-2 25 100 0 0Kodayar-1 60 100 60 60Kodayar-2 40 100 40 40
HYDRO TOTAL 1926 100 1114 1114Pillai Perumal Nallur 331 100 0 0 282 49.49
Samalpatty 105 100 101.2 101.2 225 49.70TCPL 63.5 100 57.6 57.6
Madurai PCL 106 100 105.5 105.5 214 49.74GMR PCL 196 100 186 186 212 49.74IPP TOTAL 802 450 450
TOTAL GENERATION 6523 4603 4603
AVAILABILITY OF TAMIL NADU:-TYPICAL DATA ON 04/01/2002
AFTER APPORTIONING LOSS OF 2.86%
FEATURES OF SPECIAL ENERGY METERS :• ACCURACY : 0.2 S AS PER OEC -687, 1992
• STATIC, TOTALLY TAMPER - PROOF, SEALED FOR LIFE
• GALVANIC ISLATION AND SURGE SUPRESSION
• TWO STANDARD MODELS : 110V, 1A AND 110V, 5A
• NON - VOLATILE MEMORY FOR 10 DAYS
• HARMONICS FILTERED OUT AND ONLY FUNDAMENTAL ENERGY RECORDED
• ALL MEASUREMENTS, RECORIDNG IN SECONDARY QUANTITIES. CT AND VCT RATION APPLIED IN REGIONAL COMPUTATION
• NET ENERGY ( WH) EXCHANGE IN EACH 15 MIN. BLOCK
• CUMULATIVE WH TRANSMITTAL AT EACH MIDNIGHT
• AVERAGE FREQUENCY IN EACH 15 MIN. BLOCK
• CUMULATIVE REACTIVE ENERGY EXCHANGE WHILE VOLTAGE IS 97% OR BELOW
• CUMULATIVE REACTIVE EXCHANGE WHILE VOLTAGE IS 103% OR ABOVE.
• HIGH-ACCURACY OF INTERNAL CLOCK: ONE MINUTE/MONTH,WITH RESTRICTED ADVANCE/ RETARD FACILITY
• TAGGING OF DATA WITH DATE, TIME METER NO. IDENTIFICATION OF TIME BLOCK WHEN VT SUPPLY DISTRUBED
• NO SEPARATE AUXILIARY SUPPLY ; ONLY OPTICAL COUPLER FOR DATA COLLECTION ( WEEKLY)
• DISPLAYS TO APPRISE THE SUBSTATION OPERATOR AS TO WHAT IS BEING RECORDED IN METERS MEMORY
SEB’S OPTIONS TO EVENTS
1. PROSPECTIVE REVISION OF ISGS AVAILABILITY (UPWARD/DOWNWARD)• SCHEDULE REVISED FOR REMAINING PART OF THE DAY2. TRIPPING OF A ISGS UNIT (KNOWN AFTER THE EVENT)• IMMEDIATE FREQUENCY DIP• ALL OPERATING UNITS PICK UP EXTRA MW• SEB’S DRAWAL REDUCES SEB RECEIVES UI PAYMENT SEB’S OPTIONS:(I) DRAW AS PER SCHEDULE AND FOREGO ADVANTAGE OF UI(II) REDUCE NET DRAWAL BY• INCREASING OWN GENERATION AND/OR REDUCING LOAD> RECEIVE UI PAYMENT TILL ISGS REVISES ITS AVAILABILITY AND NEW
SCHEDULES COME INTO EFFECT
3. TRIPPING OF THE SEB’S OWN GENERATING UNIT
• SEB’S NET DRAWAL INCREASES SEB HAS TO PAY UI SEB’S OPTIONS(I) CONTINUE TO OVERDRAW AND PAY UI(II) REDUCE NET DRAWAL BY• CARRYING OUT CORRESPONDING LOAD SHEDDING AND/OR RUN UP ALL AVAILABLE GENERATION(III) INCREASE ISGS REQUISITION, IN CASE FULL ENTITLEMENT WAS
NOT REQUISITIONED EARLIER(IV) ENTER INTO A BILATERAL WITH OTHER SEB/ISGS TO DRAW ANY
SURPLUS/IDLING CAPACITY
4. LOAD CRASH IN THE STATE:• FREQUENCY INCREASES• UNDER DRAWAL FROM THE GRID UI IMPLICATION (NET GAIN/LOSS)
SEB’S OPTIONS:(I) INCREASE DRAWAL BY• REDUCING OWN GENERATION (IF UI RATE IS LOWER THAN THE
RESPECTIVE ENERGY RATE)• RESTORE DISCONNECTED LOADS (IF UI RATE IS LOWER THAN THE
RECOVERY RATE)• REDUCE ISGS REQUISITION (IF UI RATE FALLS BELOW ISGS ENERGY
RATE)CONTINUE TO UNDER DRAW, IN EFFECT SUPPLYING UI TO THE GRID. THIS IS
ADVANTAGEOUS AS LONG AS THE UI RATE IS HIGHER THAN THE ENERGY RATE
FOUR SCENARIOS …1
A. FREQUENCY IS GOOD OR HIGH, AND THE STATE IS OVERDRAWING:- NO PROBLEM, AND NO ACTION REQUIRED
FOR ENHANCED OPTIMIZATION, HOWEVER TO THE EXTENT POSSIBLE.(I) REDUCE OWN GENERATION TO THE EXTENT POSSIBLE AND INCREASE
OVERDRAWAL SO LONG AS FREQUENCY IS ABOVE ABOUT 49.8 HZ.(II) RESTORE CONSUMER LOAD THAT HAD BEEN SHED, PROVIDED
TARIFF/REALIZATION RATE IS HIGHER THAN CURRENT UI RATE. (THIS ALSO INCREASES OVERDRAWAL)
(III) INCREASE ISGS REQUISITION, IF SOME PART OF THE ENTITLEMENTS HAD NOT BEEN REQUISITIONED EARLIER, PROVIDED THE FREQUENCY IS (AND IS LIKELY TO REMAIN) BELOW ABOUT 50.2 Hz. (THIS WOULD INCREASE THE DRAWAL SCHEDULE AND THEREBY REDUCE OVERDRAWAL)
FOUR SCENARIOS …2B. FREQUENCY IS GOOD OR HIGH, AND THE STATE IS UNDER DRAWING: ACTION
REQUIRED(I) REDUCE OWN GENERATION TO THE EXTENT POSSIBLE, IF THE
FREQUENCY IS ABOVE ABOUT 49.8 HZ. (THIS WOULD REDUCE UNDERDRAWAL)
(II) RESTORE CONSUMER LOAD THAT HAD BEEN SHED, AND REDUCE UNDERDRAWAL
(III) REDUCE ISGS REQUISITION, PROVIDED THE PREVIOUS TWO ACTIONS HAVE BEEN TAKEN AND THE FREQUENCY CONTINUES TO BE ABOVE 50.2-50.3 HZ. IF FREQUENCY IS LIKELY TO REMAIN ABOVE 50.2 HZ., BILATERAL SALE TO A NEEDY NEIGHBOUR CAN BE TRIED
C. FREQUENCY IS LOW, AND THE STATE IS OVERDRAWING: ACTION REQUIRED(I) INCREASE OWN GENERATION TO THE MAXIMUM POSSIBLE EXTENT(II) CURTAIL CONSUMER LOAD, LOAD SHEDDING TO BE GRADED
BALANCING BETWEEN UI PRICE AND CONSUMER CATEGORY(III) INCREASE ISGS REQUISITION TO FULL ENTITLEMENT (IF NOT
REQUISITIONED FULLY EARLIER), AND ARRANGE FOR BILATERAL PURCHASE FROM ANOTHER SEB/ISGS
FOUR SCENARIOS …3D. FREQUENCY IS LOW, AND THE STATE IS UNDERDRAWING: NO ACTION
REQUIRED; FOLLOWING CAN BE DONE FOR ENHANCED OPTIMIZATION.
(I) INCREASE OWN GENERATION TO THE EXTENT POSSIBLE, PROVIDED THE FREQUENCY IS BELOW ABOUT 49.5 HZ. (COMPARING VARIABLE COST WITH CURRENT UI PRICE)
(II) CURTAIL CONSUMER LOAD,BY SHEDDING LOW PRIORITY LOAD (PROVIDED UI EARNING FOR THE SEB JUSTIFIES SUCH LOAD SHEDDING). THIS IS TOTALLY OPTIONAL, AND HELPS THE GRID
(III) INCREASE ISGS REQUISITION TO FULL ENTITLEMENT (IF NOT REQUISITIONED) FULLY EARLIER), AND EARN UI OR SELL THE SURPLUS THROUGH A BILATERAL AGREEMENT
ACTION DEPENDS ON PREVAILING FREQUENCY, AND IS INDEPENDENT OF SHETHER OVERDRAWING OR UNDERDRAWING. IT FOLLOWS THAT ON-LINE MEASUREMENT AND DISPLAY OF CORRECT NET DRAWAL IS NOT ALL THAT CRITICAL.
MANAGEMENT OF DRAWALS
CURTAILMENT OF DRAWAL BY SEBA) IF UI RATE IS HIGHER THAN THE HIGHEST
ENERGY RATE OF THE STATIONS SCHEDULED, THEN CURTAIL DRAWAL BY MAXIMISING CHEAPER GENERATION
B) IF UI RATE IS HIGHER THAN CONSUMER LOAD NET RECOVERY RATE THEN CURTAIL DRAWAL BY LOAD SHEDDING