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SOUTHERN REGIONAL POWER COMMITTEE BANGALORE

MINUTES OF THE SPECIAL MEETING ON RGMO/MVAR HELD AT SRPC

BANGALORE ON 29TH JUNE 2013

1. INTRODUCTION

A Special Meeting on RGMO performance & MVAR Interchange of SR Generators was held at Bangalore on 29th June 2013. 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 said that the issue regarding RGMO performance and MVAR interchange was not being deliberated in detail in the OCC Meeting due to paucity of time and partial representation of the generators. Frequency profile of SR Grid was not smooth due to the relatively inadequate response observed from RGMO/FGMO with manual intervention. He brought to kind attention, extract of Order dated 03.05.2013 of Hon’ble CERC in respect of Petition No.52/MP/2012 “12. We again direct that all generating stations shall comply with Regulation 5.2(f) of the Grid Code failing which appropriate proceeding shall be initiated against them for non-compliance with the Provisions of the Grid Code and directions of the Commission.” He added that Objective analysis was required and visible performance was need of the hour. It had been informed by NLC that they had received a communication from Hon’ble Commission on RGMO/FGMO. Updated status / summary of RGMO/FGMO was presented (Annexure-II) and he requested the generators to update this information and communicate changes if any to SRLDC/SRPC. Further, any change in the status and summary needed to be communicated to OCC each month. SRLDC has suggested opening of separate Web groups to focus on the issue. Generators were required to furnish the information in the required format enabling proper analysis. Validation with respect to SRLDC/SLDC data was also required to be carried out by the Generators/SLDCs. Reactive management was a collective effort in which generators too needed to contribute for the safe and secure operation of the Grid.

2.0 RGMO/FGMO WITH MANUAL INTERVENTION

SRLDC presented the RGMO/ FGMO response for a few instances for drop in frequency as well as rise in frequency (Annexure- III). The quality of response was classified as Reverse Response (RR), No Response (NR), Insufficient Response (IR), Partial Response (PR) and Responsive (R).

Issues raised by Generators

In certain cases, units were running near technical minimum, and any rise in frequency could require oil support.

Poor quality of coal and wet coal issues etc were having an impact on RGMO/FGMO performance. There was no possibility at times for increasing/decreasing the generation

Minutes of the Special Meeting on RGMO/FGMO and MVAR Interchange held on 29th June 2013

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Some machines were having technical issues (example some thermal units of TANGEDCO, NLC II Stage I) and could not give desired RGMO/FGMO response.

Number of parameters were required to be maintained for a particular output, and at times there were issues in maintaining the parameters.

With drop in frequency, auxiliaries output was also getting affected resulting in decrease in generator output.

During drop in frequency, initial response would be available to the margins available for a few minutes. However, it would be able to sustain the level for a few minutes only.

Certain old hydro stations could operate only on FGMO with manual intervention.

SRPC/SRLDC OBSERVATIONS

It was mandatory for the following generators to put their units under RGMO/FGMO with manual intervention in accordance with the following IEGC Provision:

“5.2(f) All thermal generating units of 200 MW and above and all Hydro Generating Units of 10MW and above which are synchronized with the grid, irrespective of their ownership, shall have the governors in operation at all times in accordance with the …..”

The Regulations had been framed after detailed consultations, expert opinion, special committee recommendations etc. in which number of technical issues had been deliberated. Hence, any technical issue was required to be raised with Hon’ble Commission since exemption/extension could be granted by Hon’ble Commission only.

Disabling of the RGMO/FGMO with manual intervention features was reported by some of the generating stations. Disabling was not being informed to SRLDC. It was pointed out that disabling was to be carried out in contingency only in accordance with the following IEGC Provision:

“5.2(f)(ii)(c) If any of the Generating Units is required to be operated without its governor in operation as specified above, the RLDC shall be immediately advised about the reason and duration of such operation. …..”

Suppression of RGMO/FGMO with manual intervention was not permitted in any form, as per the following IEGC Provision:

“5.2(g) Facilities available with/in load limiters, Automatic Turbines Runup System (ATRS), Turbine Supervisory control, coordinated control system, etc., shall not be used to suppress the normal governor action any manner and no dead bands and/or time delays shall be deliberately introduced except as specified in para 5.2(f) above.”

Reverse response was also observed in a few instances, which was viewed with concern. No Response and Insufficient Response were also areas of concern. During fall in frequency, response was required only for few


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minutes and unit could be ramped back if increased level was not sustainable. Relevant IEGC Provision in this regard is reproduced below:

“5.2(h) All thermal generating units of 200 MW and above and all hydro units of 10 MW and above operating at or up to 100% of their Maximum Continuous Rating (MCR) shall normally be capable of(and shall not in way be prevented from) instantaneously picking up to 105% and 110% of their MCR, respectively, when frequency fall suddenly. After an increase in generation as above, a generating unit may ramp back to original level at a rate of about one percent(1%) per minute, in case continued operation at the increased level is not sustainable. Any generating unit not complying with the above requirements, shall be kept in operation(synchronized with the Regional grid) only after obtaining the permission of the RLDC.”

During rise in frequency, RR, NR & IR was to be looked into by generators. It appeared that RGMO/FGMO was disabled in a number of units.

Non Response of Hydro machines except few units at Sharavathy(KPCL), Idukki (KSEB), Kundah(TANGEDCO) was also to be examined by generators.

Response was to be shared by all the generators and hence putting extra burden on performing units was not justified.

Fortnightly submissions of RGMO/FGMO reports to SRLDC would be dispensed. Actual performance of the units shall henceforth only be monitored.

All the technical issues needed to be sorted out during next O&M. Schedule would be furnished to SRLDC through respective SLDC.

Commercial issues like DC declaration by the generators should not be impediments for inadequate RGMO/FGMO response.

Respective SLDC would monitor and ensure RGMO/FGMO response of the units under their control. It was noted that inadequate relief by generators would lead to tripping of df/dt & UF relays which put additional burden on the consumers.

3.0 MVAR INTERCHANGE

SRPC secretariat made a presentation on MVAR interchange (Annexure - IV)

It was pointed out that timely information had not been communicated by the following utilities:

APGENCO – None of the Stations APSLDC – GVK I, Spectrum, Lanco, BSES, KPCL – Bellary , Hydro stations KSEB- None of the Stations TANGEDCO – NCTPS, TTPS, ETPS, all gas stations TN SLDC – All IPPS ISGS – MAPS, KAIGA, NLC II, NLC I- Exp, UPCL


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CGS – Kayamkulam, NLC-I IPPS – Lanco, SEPL, Jindal

SRPC/SRLDC OBSERVATIONS

Generators connected to high voltage nodes were not absorbing VARs as per limits of their Capability Curves. In certain cases, even injection was observed at high voltages.

Injection of VARs at low voltage nodes could be improved for better voltage profile.

Validation of data was required to ensure that correct information is visible at SRLDC/SLDCs w.r.t. the actual reading at the units/station along with sign convention.

Respective SLDCs would monitor VAR Interchange of the generators under their control and ensure better voltage profile.

IEGC 3.4 (e) was pointed out as reproduced below :

“As voltage management plays an important role in inter-state transmission of energy, special attention shall be accorded, by CT, for planning of capacitors, reactors, SVC and Flexible Alternating Current Transmission System (FACTS), etc.. Similar exercise shall be done by STU for intra-State transmission system to optimize the utilization of the integrated transmission network.”

Similar regulation as per State Grid Code is to be implemented by SLDCs as given in 6.6.6 of IEGC

“The ISGS and other generating stations connected to regional grid generate/absorb reactive power as per instructions of RLDC, within capability limits of the respective generating units, that is without sacrificing on the active generation required at that time. No payments shall be made to the generating companies for such VAR generation/ absorption.”

4.0 SUMMARY/ACTION PLAN

Separate web group would be created by SRLDC for RGMO and MVAR interchange.

Each utility would intimate the Nodal Officer for RGMO and MVAR inter change. This Nodal Officer would be responsible for co-ordination and timely submission of data.

The data would be submitted in Excel format. PDF files and picture formats would be avoided.

SRLDC would post the incidents for which RGMO is to be analyzed in the web groups. The concerned utility would furnish the data in Excel format within 3 days of posting of the incidents in the web group.

It was noted that RGMO/FGMO response in some cases was in reverse direction/no response/minimal response etc, disabling of the feature was also reported. The generators would ensure performance of the


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units in RGMO/FGMO with manual intervention so that the regulatory requirements are met.

Whenever the RGMO feature is disabled the same will invariably and immediately be informed to SRLDC through the respective SLDCs along with the likely duration of disconnection, reasons and the likely time for re-enabling of the feature.

As regards MVAR interchange, the utilities would compile the unit-wise/station-wise data for the maximum as well as minimum bus voltages at the nearest node day-wise. The same would be furnished for the period 1st May 2013 to 15th July 2013 by 17th July 2013. The format for submission of the data is enclosed.

The generators would undertake demonstration of the MVAR absorption/injection from 1st July 2013. The necessary schedule for demonstration would be finalized in consultation with SRLDC through their respective SLDCs.

The tap positions of all the GTs would be set at 400 kV. Since the planned outages of the units are to be undertaken shortly, it will be invariably ensured that the tap positions are set at 400 kV during the unit outage.

It was noted with concern that in some of the instances the data was not visible and also the sign convention was reverse. The validation of SCADA data at the stations and at SLDCs/RLDC would be undertaken by the respective utilities.

It was noted with concern that some of the generators were injecting VAR at high voltages. It was therefore felt necessary that MVAR inter change by the generators (except ISGS) would be monitored by the SLDCs to ensure that the inter change is appropriate in direction and quantum. As far as ISGS stations are concerned the monitoring would be carried out by SRLDC.

Necessary instructions may be issued for strict compliance of the declared RGMO/FGMO with manual intervention features and also for MVAR inter change as per capability curve of the units. In respect of IPPs, the concerned SLDC would issue the directions.

The performance of the units as regards RGMO operation as well as MVAR inter change would be analyzed in detail in the next meeting which would be held on 25th July 2013 (Thursday) at 10:30 hrs in the Conference Hall of SRPC, Bangalore.

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