SOUTHERN REGIONAL POWER COMMITTEE BENGALURU. Record Notes of the Meeting regarding issues pertaining to Tamil Nadu

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1 SOUTHERN REGIONAL POWER COMMITTEE BENGALURU Record Notes of the Meeting regarding issues pertaining to Tamil Nadu A Meeting on issues pertaining to Tamil Nadu was held on 25 th TANTRANSCO, Chennai. The list of the participants is given at Annexure- I. February 2015 at Shri S. Ravichandran, SO welcomed Shri S.R.Bhat, Member Secretary, SRPC, Shri G. Anbunesan, AGM, SRLDC, Director (Operation), TANTRANSCO, Director (Transmission Projects), TANTRANSCO, CE (Hydro), TANGEDCO, CE (NCES), TANGDECO, CE (Transmission), TANTRANSCO and other participants to the Meeting. He stated that SRPC/SRLDC were putting in sustained efforts to resolve issues relating to Tamil Nadu system. Certain issues had technical, financial, operational and regulatory impacts, but assured that TANTRASCO/TANGEDCO were taking necessary steps to resolve the issues. Shri S.R.Bhat, Member Secretary, SRPC thanked TANTRANSCO and TANGEDCO for kindly organizing this Meeting. He congratulated Shri P S Ganesh, for assuming the post of Director (Operation), TANTRANDCO. He also congratulated Shri S. Ravichandran, on being entrusted the responsibility of Special Officer and CE (Operation). He welcomed all the participants to the Meeting. He stated that the contribution/cooperation of Tamil Nadu was well appreciated in various Committee Meetings. TANGEDCO was playing a pivotal role in respect of improvement of RGMO performance and in analysis. However, there were a few issues which were being discussed in monthly Meetings of OCC but were pending resolution. He added on account of time constraints in OCC meetings, certain issues were not getting due focus. In view of the above, this Meeting was being conducted in order to have focused deliberations on issues in the presence of higher management. Following issues were deliberated in the Meeting: Implementation of ADMS (Automated Demand Management Scheme) including Contingency Plan for wind Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 1

2 It was noted that with regard to implementation of ADMS, Hon ble CERC had issued necessary directions with regard to Petition No.265 /MP/2012 & also Petition No 120/2011. Compliance of directions was therefore highly essential. It was also noted that KPTCL and KSEB had already implemented ADMS. In Kerala the scheme had been implemented about 3-4 months back and some operations had also been observed. SRPC stated that there should not be any apprehension with regard to implementation of the scheme. Scheme would operate only when frequency was below the IEGC permissible limits while overdrawal was persisting for defined quantum of time. Hence time margin would be available to the system operators in the control room to initiate corrective actions. Contingency plan for sudden loss of wind would be required to operate instantaneously. Since, implementation of ADM scheme was a regulatory requirement, the same needed to be in place. TANTRANSCO informed that logic for the ADM scheme as well as contingency plan for loss of wind had been finalized. P&C Wing of TANTRANSCO was implementing both the schemes. Feeders of quantum of 650 MW had already been identified and same set of feeders would be utilized for contingency plan for wind also. TN also informed that this scheme would be implemented along with the ULDC scheme which was likely to come up by March It may take further 2-3 months to implement the scheme. On a query from SRPC, TANTRANSCO informed that implementation of ADMS was part of the contract being executed by M/s, Alstom. TANTRANSCO would take adequate care during SAT period. After deliberations, TANTRANSCO assured that about 100 MW (1 st Stage out of 650 MW) loads under ADMS would be ensured before 31 st March Balance quantum would be progressively implemented in 2 to 3 months. SRPC requested Tamil Nadu to furnish progress of implementation of the scheme regularly to SRPC. Activation/implementation of UV relays Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 2

3 It was noted that implementation of UV relays had been kindly agreed by TANTRANSCO in the 26 th SRPC Meeting held on 20 th December TANTRANSCO informed that the issue had been referred to field and data collection was under progress. Initially, TANTRANSCO had identified Udumalpet and Coimbatore areas for implementation of UV relay scheme. It was also pointed by TANTRANSCO that with system changes/improvement, the voltage scenario was changing in Tamil Nadu system viz. earlier Chennai area which was earlier facing low voltages but now had become a high voltage node. SRPC/SRLDC stated that UV relays may be required to act only when there was MVAR drawal from the grid with voltage level below 380 kv. It was noted that in TN system, grid feeders (above 230 kv) were having numerical relays in which UV feature could be enabled. This feature was not available in lower voltage level feeders. SRPC/SRLDC pointed out the scheme could be reviewed after implementation in the future, once the voltage profile improved. After deliberations, TANTRANSCO agreed to furnish the road map along with time schedule for implementation of UV Relay scheme during the next OCC. AUFR & df/dt schemes It was noted that Compliance Report in respect of AUFR and df/dt schemes certified by SRPC and SRLDC had been communicated to Hon ble CERC during April The compliance report consisted the following: Status of additional identified load which were to be implemented Status of additional loads to be identified and implemented Status of SCADA mapping and the action plan to achieve 100% mapping. It was noted that as per the compliance report, around 797 MW of feeders were overlapping between AUFR and df/dt schemes for which TN needed to identify additional feeders and implement the same so as to meet the deficit. Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 3

4 TANTRANSCO informed that they had already identified 568 MW of additional feeders and the same would be implemented. SRLDC/SRPC also pointed out that around 2,718 MW of feeders had been mapped against implemented quantum of 3,379 MW. It was noted that feeders up to 230 kv level had been mapped to TN SLDC while feeders below 230 kv had not been mapped due to lack of communication facility. TN informed that there were certain pending points which were to be mapped which were covered under GSES. SRPC/SRLDC stated that orders regarding implementation of GSES were awaited and in the interim period, TN needed to take steps for achieving 100% matching. After deliberations, TANTRANSCO agreed to furnish list of additional feeders identified to meet the deficit (overlapping) by first week of March Road map along with time schedules for implementation would also be furnished during next Meeting of OCC. TANTRANSCO was suggested to initiate steps to ensure 100% mapping. Action Plan in this regard would be furnished. Reactive power planning TANTRANSCO informed that for , they had planned installing 34 units (2.4 MVAR) capacitor banks at 11 kv level and 16 units (2.4 MVAR) capacitor bank at 22 kv level. They also informed that the time schedule for completion of installation of these capacitor banks was six months. TANTRANSCO informed that 7 Nos. of 168 MVAR capacitor bank at 110 kv level in Coimbatore area had been planned and approval from their Board had been received. TANTRANSCO informed that around 755 MVAR of capacitors at distribution level had been commissioned out of 1,005 MVAR capacitors planned. SRPC stated that TANTRANSCO was to identify/assess reactive power requirement in their system and furnish the status/schemes to CEA along with time schedule of implementation. Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 4

5 TANTRANSCO informed that requirement of reactors was being followed up in the SCPSPSR in coordination with CEA and CTU. LVRT feature on wind generator It was noted that all wind generators commissioned after needed to have LVRT feature as per CEA Regulations. It had also been suggested that since wind generation capacity was huge, LVRT feature may be required for existing generators also in the interest of grid security. Sudden wind withdrawal had been observed in 3 to 4 instances. TANGEDCO informed that a Meeting had been conducted with wind generators in Tamil Nadu and noted that only certain higher capacity wind generators (> 1 MW) were having LVRT features. TANGEDCO stated that this feature cannot be implemented for older machines. There were also apprehensions about safety of generators for implementation of LVRT feature in older machines. SRPC enquired about the mechanism of ensuring LVRT feature in new generators getting connected. SRLDC suggested that SLDC may take a proactive role in ensuring LVRT feature/implementation. SRPC brought to kind attention, provision of Regulation 4(8) of CEA (Technical Standards for Connectivity Distributed Generated Resources) Regulations 2013, as reproduced below: The appropriate licensee shall inform the concerned State transmission utility within 30 days of acceptance of application for connectivity of a generating station to Electricity System operating at voltage level below 33 kv. The concerned State transmission utility shall in turn inform the State Load Despatch Centers with details of installed capacity, generators capabilities, connectivity and likely date of commissioning or date of commercial operation. SRPC also informed that harmonic, flicker, dc current injection and active power control were mandated for wind generators as per CEA Grid Connectivity Regulations. Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 5

6 After deliberations, it was noted that TANGEDCO would verify whether generators (connected after ) were equipped with LVRT feature as mandated under CEA Regulations and take appropriate action in this regard. TANGEDCO would revert back on possibility of LVRT features for existing machines also. Development of Point to Point Mock Exercise Procedure (Black Start) and carrying out exercise as per the Procedure. TN informed that point to point mock exercise would not be possible in their system since consumer loads would get interrupted. They were carrying out mock exercises of generators. Earlier point to point mock test for units at Sengulam and Papanasanam had been attempted, but generator hunting was observed. SRPC pointed out that black start document was being updated every year while mock exercise was to be conducted twice a year. Black start procedure needed to be practical and implementable during any contingency in real time. It was noted that Kerala and Karnataka were conducting point to point mock exercises and the reports were also being furnished. TN informed that they were facing certain difficulty in extension of supply to load points since there was no control over loads. SRLDC requested that constraints, if any, should be clearly brought forth by TANTRANCO so that the same could be examined at their end. TN requested SRLDC to furnish the mock exercise report in respect of KSEB. After deliberations TN was requested to furnish constraints being faced in their system. The constraints would be examined/deliberated with respect to the Back Start Procedure of Tamil Nadu systems. SRLDC agreed to furnish the point to point mock exercise report of KSEB to Tamil Nadu. Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 6

7 RGMO SRLDC presented the RGMO performance of TN Hydro and TN Thermal for instance on 14 th January 2015 and 16 th December KKNPP Unit tripping Tal Kol Pole 2 tripping Hydro Thermal Total Possible Actual % Possible Actual % Possible Actual % to Hz to Hz It was observed that response from TN Hydro was poor on TN opined that hydro response could have been poor, since many stations were irrigation based. TANGEDCO informed that they were observing RGMO response in the range of about 4-5 % of unit capacity in respect of NCTPS and TTPS stations. MTPS units were in FGMO with MI mode and were responding. TANGEDCO opined that presently the grid was quite stable and hence it was difficult to find relevant instances for RGMO performance assessment. TANGEDCO informed that RGMO had been implemented for both the units of NCTPS St- II. RGMO for MTPS St- III unit (600 MW) would be implemented by June After deliberations, it was agreed that TN would revert back with unit-wise analysis on the above instances. All instances being posted by SRLDC in the web group would be assessed for RGMO performance by TANGEDCO/TN SLDC. TN was also requested to take up issue of non-performing units with SERC in line with Order of Hon ble CERC on Petition No.302/MP/2013. Auto Reclose for 400 kv Mettur- Arasur lines Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 7

8 TANTRANSCO informed that A/R for 400 kv Mettur- Arasur lines would be implemented after commissioning of 400 kv MTPS-Thiruvalam lines. TANTRANSCO informed the works for a single span was only pending for Thiruvalam- MTPS line. Permission from Hubli Railway Division for one Railway crossing was awaited. TANTRANSCO also informed that the 400 kv Mettur-Thiruvalam line was expected to be commissioned before March Discrepancy in wind generation data of NCES & SLDC TN stated that wind generation data would not match with the SLDC data since energy was not getting accounted in the same month. Generation detail being furnished by NCES was being obtained from various electricity distribution circles (EDC) every month with different meter reading cycles. Generation details furnished by TANTRANSCO pertained to daily data. Further, generation data furnished by NCES was at wind farm HT service end, whereas TANTRANSCO data was at pooling station end which included some loss. Hence generation data furnished by TANGEDCO would not tally with TANTRANSCO data. TANGEDCO informed that this issue would be resolved with installation of SEMs with AMR facility. Action in this regard had already been initiated. After deliberations, it was agreed that TANGEDCO NCES wing would continue to furnish the data to SRPC and CEA. TN SLDC would continue to furnish the operational data to SRPC. Implementation schedule of SEMs with AMR facility would be furnished by TANGEDCO to SRPC/SRLDC. LGBR imbalance in Chennai area during weekends affecting flows on 400 kv Kolar- Hosur Lines TANTRANSCO informed that demand throughout the state and also in Chennai area was less on account of extreme cold weather conditions. Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 8

9 SRLDC presented flow pattern of 400 KV Kolar-Hosur lines on working day ( ) and holiday ( ), S1-S2 corridor flow and generation levels at NCTPS (Presentation copy at Annexure- II). It was observed from the same that generation level at NCTPS was remaining same during holidays and working days. It was also observed the flows on Kolar-Hosur lines was relatively more, though flow through S1-S2 corridor was less on holidays compared to working days. TANTRANSCO stated that this phenomenon was not on account of load generation imbalance at Chennai area. They added that it may be due to higher schedule of Kerala. TN observed that line loadings of Kolar- Hosur was more whenever schedule to Kerala was on the higher side. For one instance TN intimated that when Kerala schedule was 1,858 MW, Kolar-Hosur flow was around 510 MW/ each line and when Kerala schedule was 1,717 MW the flow in Kolar-Hosur was around 450 MW/each line. TN informed that they had conducted system studies and had observed that there was no impact on Kolar-Hosur line flow due to any LGBR skewing in Chennai area. TN also informed that they were backing down generation in NCTPS and Gummidipoondi area also. The generation levels in all private generators were also being minimized. TN opined that when 400 kv Mettur-Thiruvalam lines are commissioned the situation may improve. TANTRANSCO informed that maximum demand levels at Chennai area on and were as below: ,450 MW ,800 MW SRLDC/SRPC pointed out that in general there was a huge demand difference in Chennai area on holidays as compared to working days. It was pointed out that Kolar-Hosur loading was generally high and with skewed LGB of Chennai area the line loading were reaching violation levels. The net power outflow from Chennai area on holidays and weekdays needed to be assessed. Matching generation reduction was to be planned with respect to any fall in demand. Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 9

10 It was noted that North Chennai Stage-II units were not being backed down due to some technical problems which were being addressed. SRPC/SRLDC agreed that they would study reasons for increased flow on Kolar- Hosur lines on holidays which would be deliberated in the OCC Meeting. TANGEDCO would take action with respect to backing down of North Chennai Stage-II unit up to the technical minimum. Energy Generation Data Management from Renewable Energy Sources Action taken with respect to Meeting held on 8 th November TANGEDCO informed that they had a Meeting with NCES generators yesterday and the decisions would be put up to their Higher Management. With respect to the decision finalized in the Meeting held on 8 th November 2013 at Chennai. TANGEDCO/TANTRANSCO agreed to furnish item-wise reply to CEA/SRPC. Status update on evacuation schemes for wind evacuation It was noted that TANTRANSCO had agreed to furnish the details in the 26 th SRPC Meeting held on 20 th December TANTRANSCO agreed to furnish the scheme wise (as per 36 th SCPSPSR Minutes) updates to SRPC before next OCC. Power purchases planned from IPPs/CPPs during TN informed that planned generation levels at IPPs/CPPs for the year had been reduced by CEA in the Annual Generation Target Meeting. TN agreed to furnish the data in this regard in the next OCC. Resumption of full pumping operation in Kadamparai. TN informed that Unit-I & II were operating in generation as well as pumping modes. Unit-III was working only in generation mode since Digital Frequency Converter was Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 10

11 required to be installed. It needed total shutdown of the unit and was planned to complete by end of May Unit-IV had been under shut down since long time and was expected by September TN was requested to kindly expedite so that pumping operations could take place during instances of sustained underdrawal. Under drawal by TANTRANSCO SRLDC had reported following instances of persistent under drawal by Tamil Nadu for analysis (Annexure- III) : 12 th December :50 to 22:26 hours 12 th January :00 to 03:00 hours 12 th January :00 to 05:00 hours 25 th January :30 to 18:30 hours TANTRANSCO informed that they had replied regarding the above instances along with action taken by TN SLDC. Copy of TN letter is given at Annexure- IV. TN informed that on 12 th January 2015, actual HT relief was 750 MW against the anticipated relief of 1,000 MW. Based on the anticipated relief advance action was taken modulate generation in order to reduce the under drawal. Load reduction in TN system particularly during night hours was due to severe cold weather conditions. They were taking measures to avoid under drawal like surrender of CGS power, backing down of thermal and other generations. It was informed that there was backing down of about 1,500 MW due to low demand on On a query whether Units were going up to technical minimum, TN informed that they were going close to technical minimum which was at 70% of unit capacity. TANGEDCO informed that there were some problems in NCTPS Unit-II (210 MW) due to Axial shift problem. Hydrogen gas leak identified during testing Mettur TPS St-III unit had been rectified and the unit was under observation. TN also informed that MTOA leveraging up to 80% would be considered. Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 11

12 OTHER ISSUES Operating Basin Bridge units in condenser mode in order to keep voltage within limits TN SLDC informed that Basin Bridge units were being run in condenser mode as per grid requirement. PSSE base case submitted by TN SRLDC pointed out that the data shown in assumptions was different from data entered in the in PSSE base case submitted for June 2015 TN assured that the issue would be referred to System Studies Wing and corrective action would be taken. Bus 1 at Kayathar S/S SRLDC pointed out that TANTRANSCO was to put Bus 1 in service at Kayathar S/S TANTRANSCO informed that today ( ), it had been programmed to charge Bus-1 at Kayathar S/s MO issues/commercial Points SRLDC presented the commercial points pertaining to Tamil Nadu which are enclosed at Annexure- V SRLDC pointed out STCMS was not sending weekly SEM data and requested TN instruct STCMS for the same. SRLDC pointed out that Theni had reported time drift of 48 minutes and requested TN to look into it. SRLDC pointed out that old SML SEMs of B type (5 Amps) are installed at the following stations and facing some time drift problem: 230kV Moozhiyar line at Theni 230kV Idukki line at Udumalpet 230kV Chittoor line at Thiruvalam Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 12

13 SRLDC pointed out that standby SEM at 230 kv Villupuram on NLC TS-II Stage-I line was yet to be installed. TN confirmed that SEM at Villupuram had been installed. SRLDC pointed out that the information regarding the change in STU rates for STOA needed to be intimated in time. TN assured for timely communication. It was agreed that a workshop on SEM data handling would be held by SRLDC at Chennai. TN would communicate the date in due course. Vote of Thanks Shri G. Venkatesan, SE(LD&GO), TANTRANSCO thanked SRPC for having conducted the Meeting with TN at Chennai. He also thanked Director (Operation) and Director (Transmission Projects) for giving support to the Meeting. He stated that a number of actionable points were there for which both TANGEDCO and TANTRANSCO had to put in concerted efforts. He conveyed full cooperation and endeavor of TN in resolution of the issues. ******* Meeting with TANTRANSCO/TANGEDCO held on 25 th February 2015 Page 13

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