• The backing down of wind and solar generation is done after giving instructions to all thermal generators for backing down upto technical limits.
  • The following are relavent regulatory clauses for backing down.
  • Compendium of CERC(DSM Regulations) clause 7.1 The over drawl/Under drawl by any buyer shall not exceed 250MWfor renewable rich state.
  • compendium of CERC(IEGC) Regulations clause 5.4.2(a) SLDC/SEB/Discom shall intiate action to restrict the drawl of its control area, from the Grid within the drawl schedule.
  • compendium of CERC(IEGC) Regulations clause 5.2.(m) all SEBs,SLDCs,RLDCs and NLDC shall take all possible measures to ensure that Grid frequency remains with in (49.90Hz-50.05Hz) the band.

Following are the instructions issued from SLDC for curtailment of wind generation with written justification

DateBlock NoTimesolar cutailmentWind CurtailmentTotal Wind CurtailmentSolar generationWind generationInstantaneous FrqeucnyInstantaneous UD/ODThermal Units StatusJustification for Backing down
01-08-20193207:50 20%20% 2775 MW50.08-422Back DownTo control under-drawl at high frequency
01-08-20194611:25 20%40% 2708 MW50.05-232Back DownTo control under-drawl at high frequency
01-08-20194811:52 -10%30% 2222 MW50.02274Back DownReleased as per the grid requirement
01-08-20195112:38 10%40% 2370 MW50-419Back DownTo control under-drawl beyond 250MW
01-08-20195613:43 -10%30% 2245MW49.99122Back DownReleased to control over-drawl.
01-08-20195613:50 -10%20% 2340MW50511Back DownReleased to control over-drawl beyond 250MW
01-08-20195814:16 -10%10% 2636MW49.89126Back DownReleased due to low frequency and low solar generation at that time
01-08-20196014:47 10%20% 2920MW50.13-463Back DownBackdown given to control heavy under-drawl at high frequency and increase in solar generation
01-08-20196014:59 20%40% 2780MW49.98-625Back DownBackdown given to control heavy under-drawl and increase in solar generation
01-08-20196215:21 -10%30% 2300MW49.93685Back DownReleased as per grid requirement due to fall in frequency and solar generation
01-08-20196215:27 -20%10% 2388MW49.89703Back DownReleased as per grid requirement due to fall in frequency and solar generation
01-08-20196315:36 -10%0% 2800MW50.03489Back DownReleased as per grid requirement due to fall in frequency and solar generation
01-08-20196516:07 10%10% 3020 MW50.06-15Back DownBackdown given due to high frequency
01-08-20196816:54 10%20% 2867MW50.06-256Back DownBackdown given due to fall in demand during evening hours as well as to control high frequency underdrawl
01-08-20196917:10 10%30% 2678MW50.08-175Back DownBackdown given due to fall in demand during evening hours as well as to control high frequency underdrawl
01-08-20197318:12 -20%10% 2450MW49.95198Back DownReleased to meet the increased demand as per the grid requirement
01-08-20197719:03 -10%0% 2700MW49.85180Back DownReleased to meet the increased demand as per the grid requirement and low frequency conditions prevailed
01-08-20198019:55 10%10% 2788MW50.03-210Back DownBackdown given to load crash and to control heavy under-drawl
01-08-20198120:10 20%30% 2787MW49.96-612Back DownDemand fell due to rains at several places across the state and hence backdown is given
01-08-20198320:35 -20%10% 2383MW49.77-145Back DownReleased due to very low frequency and to support the grid with maximum injection (Up to 250MW)
01-08-20198521:09 -10%0% 2109MW49.87139Back DownReleased due to very low frequency and to support the grid with maximum injection (Up to 250MW)
02-08-20194210:21 10%10% 2821MW50.06-413Back DownTo control heavy underdrawl beyond 250MW and increase in Solar Generation
02-08-20194310:30200 MW  740 MW 49.99-213Back DownTo control heavy underdrawl beyond 250MW presented from half hour onwards and load is falling trend
02-08-20194511:00-200  720 MW 50.05-9Back DownReleased totally for increasing load trend
02-08-20196014:50 -10%0% 2660MW49.8965Back DownReleased due to very low frequency and to control the overdrawl to minimum and adhere to scheduled power
03-08-20193408:30 10%10% 2920MW50-369Back DownBackdown given to control heavy under-drawl and increase in solar generation
03-08-20193608:47 20%30% 2850MW50.06-441Back DownBackdown given to control heavy under-drawl at high frequency and increase in solar generation
03-08-20193809:30 10%40% 2550MW50.1-156Back DownBackdown given to control under-drawl at high frequency and increase in solar generation
03-08-20194009:50 10%50% 2350 MW50.03-102Back DownBackdown given to control under drawl
03-08-20194410:50 20%70% 2065MW50.03-192Back DownBackdown given to control under drawl
03-08-20195413:18 -10%60% 1705MW50.06371Back DownReleased as per the grid requirement
03-08-20195613:52 -10%50% 1854MW49.94205Back DownReleased as per the grid requirement and prevailing low frequency conditions
03-08-20195914:35 -20%30% 2020MW49.93221Back DownReleased as per the grid requirement and prevailing low frequency conditions
03-08-20196014:48 -10%20% 2317MW49.9435Back DownReleased as per the grid requirement and prevailing low frequency conditions
03-08-20196115:13 -10%10% 2631MW49.9-97Back DownReleased as per the grid requirement and prevailing low frequency conditions
03-08-20196215:20 -10%0% 2745MW49.9101Back DownReleased as per the grid requirement and prevailing low frequency conditions
03-08-20197017:30 10%10% 2992MW50.03-195Back DownBackdown given due to low load conditions
03-08-20197418:25 -10%0% 2845MW50.02126Back DownReleased to meet the demand requirement which is rising
04-08-20193408:25 20%20% 2693MW50.03-209Back DownCurtailment due to low demand
04-08-20194009:50 20%40% 2690MW50.0878Back DownTo control under-drawl at high frequency
04-08-20194110:02 10%50% 2442MW50.1-29Back DownTo control under-drawl at high frequency
04-08-20194410:55 10%60% 2148MW50.05-148Back DownTo control under-drawl at high frequency
04-08-20194411:00 10%70% 2075MW50.1-145Back DownTo control under-drawl at high frequency
04-08-20194411:05 10%80% 2050MW50.06-53Back DownTo control under-drawl at high frequency
04-08-20194411:05150  835 50.06-53Back DownTo control under-drawl at high frequency(informed to Ghani but not complied)
04-08-20194511:17 -10%70% 1505MW49.96402Back DownReleased due to prevailing low frequency conditions
04-08-20194811:50 -20%50% 1621MW49.93143Back DownReleased due to prevailing low frequency conditions
04-08-20195313:06 -10%40% 2104MW49.93165Back DownReleased due to prevailing low frequency conditions
04-08-20195413:30 -10%30% 2315MW50.05177Back DownReleased due to prevailing low frequency conditions
04-08-20195714:03 10%40% 2530MW50.16-221Back DownBackdown given to control underdrawl at high frequency
04-08-20196315:42 -10%30% 2321MW49.99151Back DownReleased to meet the demand due to fall in Solar Generation
04-08-20196917:04 10%40% 2527MW50.07-236Back DownBackdown given due to high frequency
04-08-20197318:04 10%30% 2296MW50.1-216Back DownTo Control under drawl at high frequency
04-08-20197418:27 -10%20% 2377MW50193Back DownTo Control over drawl at low frequency
04-08-20197518:41 -10%10% 2597MW49.92143Back DownTo Control over drawl at low frequency
04-08-20197719:07 -10%0% 2881MW49.85-25Back DownReleased due to prevailing low frequency conditions & to inject to grid upto 250 MW