SOUTHERN REGIONAL POWER COMMITTEE BANGALORE. MINUTES OF THE SPECIAL MEETING ON RGMO/MVAR HELD AT SRPC BANGALORE ON 29 th JANUARY 2014

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1 SOUTHERN REGIONAL POWER COMMITTEE BANGALORE MINUTES OF THE SPECIAL MEETING ON RGMO/MVAR HELD AT SRPC BANGALORE ON 29 th JANUARY INTRODUCTION A Special Meeting on RGMO performance & MVAR Interchange of SR Generators was held at SRPC, Bangalore on 29 th January The list of Participants is furnished at Annexure-I. Shri S.R. Bhat, Member Secretary I/c, SRPC welcomed the participants to the Special Meeting. He informed that earlier Meetings in this regard were held on 29 th June 2013, 25 th July 2013 and 30 th September He added that though this was the fourth Meeting that was being held and there was some visible improvement on the MVAR front. However, the RGMO performance was not up to desired level. Only around 15 to 20% of anticipated relief was being obtained through RGMO response. The response from thermal stations was considerably lower which a matter of concern. He informed that the performance of RGMO is being monitored at apex level and Additional Secretary; MoP had held a meeting on 13 th January 2014 on the matter of RGMO operation, post SR - NEW grid synchronization. He said that as all the Members were aware, SRLDC had already filed petition before Hon ble CERC which had been listed for 25 th February He also pointed out that there was some discrepancy with regard to the declaration of RGMO status. This needed to be reconciled during the course of the Meeting. Efforts of SRLDC in carrying out detailed unit wise analysis both in respect of RGMO and MVAR interchange was placed on record. He observed that there was some improvement with regard to tap optimization by generators. He informed that during 91 st OCC meeting held recently at Raichur, SRPC officers also had the opportunity to witness MVAR demonstration at Raichur TPS along with the joint testing team. He said that accuracy level of the system data visible to the operators was a matter of concern. Thus Data validation and meter calibration was the need of hour. Generating stations besides focusing on MW generation also need to focus on grid requirements such as RGMO, MVAR performance etc. The awareness and severity of the situation needed to 1

2 percolate to the ground level also. The team comprising of officers from SRLDC, SRPC and TANGEDCO had completed the MVAR capability testing in Raichur, Nagjheri, Kadra and Kodasalli generating stations of KPCL. He thanked KPCL for the cooperation extended in this regard. He placed on record the efforts of Shri M. Venkateshan, Sr Engineer SRLDC in carrying out the MVAR capability testing. He mentioned that the presence of member from SLDCs is very much essential and being the identified member of joint testing team they also needed to be involved in the testing of MVAR capability of generators. It was noted that a number of stations had not furnished MVAR data in the specified format as well as the data reaches till the last minute. KKNPP had submitted the MVAR data in graphical form and that too after follow up. It was also noted that there was no representation from KKNPP in the meeting. RGMO/FGMO WITH MANUAL INTERVENTION SRPC made a presentation timeline wise (past five months) to analyze the improvement in the observed RGMO response (Annexure-II). It was noted that the response continued to be minimal and there was considerable scope for improvement. SRLDC presented detailed analysis in respect of 6 instances of fall in frequency- 3 instances before synchronization with NEW grid and 3 instances post synchronization. DGM, SRLDC informed that field values wherever considered appropriate had been replaced in place of SCADA values. The summary for Southern Region (for fall in frequency cases) is furnished below: Date Start Time 21:01 10:02 16:37 5:32 21:30 20:27 End time 21:03 10:04 16:39 5:33 21:31 20:29 Start Frequency End Frequency Page 2

3 %Hydro Response %Thermal Response % Response Detailed state-wise analysis is enclosed as Annexure-III. Some of the generators pointed out that the fall in frequency observed at some of the stations was not adequate for RGMO response. Hence, it was agreed not to consider the incident of 12 th January 2014 for RGMO analysis. It was noted that the thermal response on 02 nd January 2014 and 07 th January 2014 was relatively higher on account of natural ramp up of generation and could not be fully considered as RGMO response. List of generators/units which were on bar and had not responded even on one occasion is enclosed as Annexure-IV. Some of the Generators such as NTPC Simhadri, NTPC Ramagundam Tuticorin TPS, North Chennai TPS and JSWEL were analyzing the incident/furnishing feedback etc. which was appreciated. The feedback details furnished are at Annexure-V. Following were the deliberations with respect to the Generators/Constituents: APGENCO/APTRANSCO KPCL It was appreciated that APSLDC was conducting regular Meetings with the state generators to improve RGMO response. Some of the stations such as Rayalseema TPP were switching off the RGMO features when the units were operating near technical minimum. APSLDC clarified that RGMO features were to be always in operation. It was noted that original equipment for KPCL hydro stations had been supplied by M/s Alstom, M/s BHEL and M/s Andritz. KPCL was proposing to entrust the work to OEM since the same was proprietary in nature. As per clause 5.2(f) of the above guidelines the proposal of implementation of RGMO in total of MW of hydro stations and 2720 MW of thermal stations had been taken up by KPCL. The status of RGMO implementation was presented (Annexure-VI). Analysis for Raichur and Bellary TPS was presented (Annexure-VII). Page 3

4 Bellary Unit RGMO was being disabled near the declared technical minimum of 350 MW. It was however noted that the unit was running up to 329 MW as per the data furnished. KPCL was requested to analyze the technical minimum limit of the unit. NTPC Ramagundam It was informed that RGMO analysis was being carried out at the station for all the instances where the fall/rise was greater than 0.03 Hz/sec on a daily basis. It was observed that whenever there was a sudden jump of MW there was a fall in pressure of about 7-8 kg/cm 2 and sustainability of generation was difficult. Therefore, the limit is set just below 25MW level. Ramagundam and Simhadri suggested that 2 minute analysis could be considered since in some instances, the generation was rising even after a period of one minute. It was pointed out that in some thermal stations the generation was seen to be falling after one minute due to sustainability issue and analysis would be carried out for one minute. Simhadri The analysis and the action plan to improve RGMO performance at Simhadri is enclosed at Annexure-VIII. Unit IV was not giving the desired result due to poor boiler response and the issue was being resolved. Stage-II units were not picking up as per desired level and the issue was being looked into. Simhadri suggested that 60 second analysis could be taken up. It was pointed out that there were SCADA limitations and minute wise analysis only would be carried out. Generators were suggested that they were free to submit the second wise analysis to SRLDC/SRPC. Simhadri also stated that the changeover were putting lot of strain on machines and the effect needed to be controlled. SRLDC stated that though the number/quantum of changeovers had reduced but still few frequency excursions were being observed. NTECL It was noted that response of NTECL units was insignificant during the instances considered for analysis and required to be improved considerably. NTECL informed that coal supply from MCL was limited. The blending ratio was also varying and hence RGMO response was not up to the desired level. NTECL informed that they will submit the details of instances captured by them where their units have contributed effectively. TANGEDCO Page 4

5 Tuticorin TPS Analysis for 14 instances is enclosed as Annexure-IX. It was noted that initial correction with respect to f was only getting activated and then it was going into hold mode for 3 minutes. Full response of 5% was not getting realized and it appeared that the scheme was not meeting the IEGC requirement. It was suggested that TTPS may get in touch with NTPC Ramagundam and Simhadri of and plan corrective action appropriately and take-up with M/s. BHEL on urgent basis. Mettur TPS Report and analysis submitted by Mettur TPS is enclosed as Annexure-X. Since the Units are FGMO with manual intervention, to maintain the operating parameters of the Boiler/Turbine/Generator at extreme permissible level, continuous training had been given to the operators to have better performance of the FGMO with Manual Intervention. The performance status was continuously being monitored at higher level and suitable instructions and guidelines had been given accordingly. It was appreciated that despite the unit being under FGMO with MI the units had given response/partial response on number of occasions. JSWEL KSEB NLC Presentation made by JSWEL is at Annexure-XI. It was pointed out that in few instances the natural ramp of increase in generation was there and could not be considered as RGMO response. It was observed that there was mismatch between SCADA and the generator MW figures. Karnataka SLDC and JSWEL were requested to sort out the mismatch. The status and the analysis presented by KSEB is enclosed as Annexure-XII. The issue was being discussed on a monthly basis in meetings. Generator control room and SLDC control room were coordinating regarding RGMO response. Generator control room personnel were being sent for training to SLDC to study RGMO/MVAR requirement. Some of the stations capacity was less than the installed capacity and the de-rated capacity may need to be considered for analysis. It was clarified that KSEB would need to take up the issue of de-rated capacity with CEA and only installed capacity would be considered for analysis/reporting. Data logging facility was not available at some of the stations. Page 5

6 UPCL It was informed that NLC had invested in RGMO implementation and were committed to meet regulatory requirements. Requirement of harmonizing commercial and operational aspects was also highlighted. UPCL presentation is furnished at Annexure-XIII. It was noted that MW and frequency could be represented in the Primary Y and Secondary Y Axis with proper scale. It was noted that the generation was not sustaining and was falling down after a minute in few instances which needed to be addressed. It was observed that there was mismatch between SCADA and the generator MW figures. Karnataka SLDC and UPCL were requested to sort out this mismatch. Action Plan finalized after deliberations: Data validation would be carried out between state generators and the respective SLDCs and the ISGS generators and SRLDC. Validation exercise would be completed and compliance report would be furnished by 15 th February Action plan to ensure the RGMO / FGMO with MI performance in Southern Region near to the level mandated in & compliance of IEGC Regulations with would be furnished by 15 th February 2014.by all the generators. The respective SLDCs shall co-ordinate in this regard and ensure effective implementation. It was agreed to continue analysis for one minute; however generators could furnish 60 second/120 second data for consideration. It was decided that SRLDC would post events for analysis within 3 days of the incident and the generators would revert back with analysis/comments within 3 days of the posting of the event in the web group. It was noted that the frequency excursions were still continuing and states were requested to stagger the changeover and minimize the effect on the Regional Grid/generators. It was recommended that all the stations should have data logging facility (up to six months) for fruitful analysis/deliberation. RGMO should always be in service including at technical minimum level. Generators would initiate steps to ensure visibility of RGMO status (On/Off) in the SCADA system by extending status data to respective SLDCs / SRLDC. Parameters would be maintained so as to ensure that RGMO response is available at all instances. SLDCs also to take proactive role for RGMO implementation/monitoring. In addition to the participation of members from generating stations, representation from respective SLDCs shall be ensured in all the future meetings of RGMO & MVAR performance analysis. TN SLDC to ensure participation/data furnishing of data in respect of STCMS units. Page 6

7 Representation from hydro stations of APGENCO and TANGEDCO to be ensured. It was agreed that status of FGMO not operational/functional in respect of KSEB stations would be considered as locked governor/constant MW in CEA/MoP status report. The RGMO shall be always in service including at Technical minimum level. The SLDCs may facilitate scheduling such that the RGMO performance is being ensured at all generation level. In case of technical limitation that warrant to keep the RGMO / FGMO out of service temporarily, the same needs to be communicated to SRLDC immediately and obtain consent for the same. Whenever there is a situation of wide valve open condition at lower generation level due to coal quality, the operator would suitably adjust the load set point of the generator to current generation level, such that performance of RGMO / FGMO with MI is ensured. 3.0 MVAR INTERCHANGE SRPC Secretariat made a presentation on MVAR interchange (Annexure XIV) with timeline. SRLDC made a detailed unit-wise presentation (Annexure-XV). List of Units which had furnished MVAR data is furnished at Annexure-XVI. Following are the salient points of the Presentation/deliberations: Kothagudem unit XI (APGENCO), Bellary unit I (KPCL) were absorbing MVAR but there was scope of improvement at higher voltages. As a station, Ramagundam NTPC was performing reasonably well. However injections at high voltages required to be controlled. Taps to be kept at same voltage level to avoid circulation of MVAR. As a station Simhadri NTPC was performing quite well. NTECL Vallur unit I had furnished un-validated data. Tap position to be confirmed. SEPL & MEPL unit absorption was being restricted (up to 30 MVAR) and considerable margin was available w.r.t. Capability Curve. MEPL/SEPL stated that there were restrictions on MVAR absorption by their OEM. It is observed that the units were operated with Vref higher than nominal, thereby inadequate absorption of MVAR. It was suggested to sort out this issue and absorb up to limits as per capability curve. UPCL units could improve absorption capability as per the capability curve. Kaiga Stage-I units were absorbing and injecting and sometimes beyond the Capability Curve. Injections to be controlled and data validation to be done. Page 7

8 Kaiga Stage-II units were absorbing and injecting. Injection at high voltage to be controlled by Kaiga GS. Scope for improvement. Injections to be controlled and data validation to be done. Raichur units I, II, III absorbing/injecting as per the tap position. Tap positions could be changed from 11 ( kv) to 12. Raichur unit IV absorbing/injecting as per tap position. Scope for higher absorption at higher voltage. Kadra unit I (KPCL) injecting at high voltages to be controlled. KPCL stated that they would examine the issue. VTS Unit-I & II considerable scope of improvement. Unit IV, V, VI & VII doing reasonably well. More absorption would be ensured if tap positions are changed. Srisailam unit 1, 2, 3, 4, 5 & 6 absorbing up to 60 MVAR at all voltages. Could consider increase in absorption with the increase in voltage. NLC Stage II units injecting as per grid requirement. TTPS injecting as per grid requirement/tap position. NCTPS injecting as per grid requirement/tap position. Unit III injection at low voltages to be improved. MTPS confirmed that the limiter in AVR/DVR of all the 4 units have already been set as per the capability curve. Feedback and recommendations by SRLDC on Reactive Power Demonstration carried out at Srisailam, Nagarjunsagar & Vijayawada APGENCO stations and at Raichur, Kadra, Kodasalli & Nagjheri stations of KPCL is at Annexure-XVII. SRLDC stated that being a member of joint test team, respective SLDCs needed to participate in the MVAR capability testing of the generators under their control area. At Kodasalli stations the AVR voltage was not able to go below kv (nominal 11 kv) which needed to be studied. SRLDC pointed out that Kaiga GS had not participated in MVAR demonstration testing at Kadra and Kodasalli despite repeated follow ups. Kaiga GS representative stated that due to man power constraint on that particular day, they were unable to participate in the testing. APGENCO to revert back regarding MVAR absorption in condenser mode of its units at Srisailam Left Bank. KPCL pointed out that Kadra and Kodasalli stations were peaking stations. With the suggested tap position, it may be difficult to close the line as the voltage differential would be very high. It was suggested that the present tap at 225 kv could be continued and if voltage profile improves it may be later changed to 220 kv. SRLDC stated that KKNPP had furnished certain details in which it was pointed out that MVAR absorption was not necessitated. The Page 8

9 details have been forwarded to CTU for comments/clarifications. However, it was clarified that KKNPP should absorb MVAR as per the requirement in line with IEGC Regulation. Clause 4.6.1(b) of IEGC is reproduced below: The person already connected to the grid shall also provide additional reactive compensation as per the quantum and time frame decided by the respective RPC in consultation with RLDC.. MS I/c, SRPC suggested a separate meeting may be called to sort out the issues with KKNPP. The updated status on tap change/recommendations is furnished below : Station Unit Present Tap Recommended Remarks and Corresponding Voltage (in kv) Tap and Corresponding Voltage(in kv) Simhadri 1, 2, 3 & 4 5 & & 399 Kaiga I 1 &2 6 & & Kaiga II 3&4 3 & & 399 VTS 1 & & & & & & 400 As per data tap for Unit 5 & 6 appears to be at 11 (230 kv) KTS 2, 3, 4 5 & 6 7 & 8 9 & 10 9 & & & & 230 Suggested to come to 220 kv in stages & & 400 Kakatiya 5 & & 400 Rayalseema 1,2,3,4&5 12 & 227 Suggested to come to 220 kv in stages Srisailam LB 1,2,3,4,5 & 6 9 & & 400 RTPP agreed to change to during next opportunity. Srisailam RB 1,2,3,4,5,6 & 7 Nagarjunsagar 1 2,3,4,5,6,7&8 10 & & & & & & 220 Lower Sileru 1 & 2 3 & 4 Upper Sileru & & & & & Could be kept at same voltage to avoid Maximise absorption Maximise absorption. It was informed that tap of Page 9

10 IPPs of AP 4 4 & circulation unit 1 & 2 were mechanically locked It is recommended that all IPPS under APSLDC could be advised to change their Tap position corresponding to voltage level of 220 kv. Recommendations given in APTRANSCO letter dated to be followed SEPL 1 &2 13 & & 399 MEPL 1 &2 13 & & 399 Bellary TPS 1 4 & 410 Could be examined to change to 5 & 400 Raichur TPS U1,2,3 Raichur TPS U4,5,6,7 & & & 222 To be confirmed. Subsequently would go to 220 kv in future. 4,7,8 & 5 & TTPS 1, 2, 3, 4 & 5 8 & 243 Could examine changing the tap to 7 as low voltages have improved. MTPS 1,2,3 & NCTPS 1,2,3 5 & & 230 Idukki All Units Changed to 1(236.5 kv) Idamalyar HEP 1,2,3 Unit 1,2 & 3 changed to 2 (115.5 kv) Lower Periyar 1,2,3 4 & & Agreed to change in next Overhaul Sabarigiri 1,2,3 & 5 4 & Kadra PH 7 & Kodasalli 7 & Nagjheri 4 & & 225 NTECL Vallur 1 & 2 Tap position to be confirmed UPCL 1 & 2 3 & After deliberations following action plan was recommended: All other stations to ensure their GT Tap positions are optimized so as to bring Grid Voltages to Nominal values. Respective SLDCs would monitor VAR Interchange of the generators under their control and ensure better voltage profile. Respective SLDCs would also participate in reactive power demonstration testing along with the testing team for the units under their control area. Page 10

11 SRLDC could issue messages for Violation of IEGC clause All Generators agreed to take action on the recommendations. Dates of Tap changes and set tap positions needed to be communicated to SRPC/SRLDC as and when changes are carried out. The same should also be reflected in the information which would be furnished for future analysis 400kV Tap changing is to be carried out only after concurrence of SRLDC. Number of Generators were not furnishing timely information. It was empahsized that information should be furnished in a timely manner. Demonstration of MVAR capability was tentatively planned for Simhadri station around 20 th February Calibration of meters needed to be undertaken to ensure accurate visibility of the parameters to the plant operators. Limiter setting would be as per the capability curve. Some of the stations AVR voltage control was not going to +/- 5%. The same would be examined and rectified. Stations could undergo themselves reactive demonstration periodically as per the Procedure. It was agreed that the demonstration of MVAR would be carried out only up to 95% of the rated auxiliary voltage. The MVAR data to be posted on sr_voltage@googlegroups.com. Data to be validated and to be submitted in the format already circulated. It was recommended that all stations should have data logging facility (up to six months) for fruitful analysis/deliberation. Any, change in capability curves w.r.t. as furnished for MVAR document would be communicated. Wherever, capability curve is not clear information can be sent in table format also. MVAR capability demonstration testing of NTPC Simhadri by the joint team is scheduled on 20 th & 21 st February 2014 where in members from NLC and APTRANSCO would also participate. On completion of the same, further schedule for testing of MEPL and SEPL would be finalized. MS I/c, SRPC thanked the participants for their contribution. He expressed hope that the generators would take positive steps on the recommendations finalized in the meeting. Timely and validated information was required to be posted on the respective web groups. ******** Page 11