6E- Chapter 2009-10-Final - Welcome to Western Regional Power …wrpc.gov.in/annualreport0910/chapter6.pdf · · 2011-03-02envisaged that in case of fuel shortage in a thermal generating

WRPC Annual Report 2009-10

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C H A P T E R - 6

MEETINGS 6.1 MEETINGS OF THE WRP COMMITTEE

During the year 2009-10, three meetings of WRP Committee were held wherein,

operational, commercial and other technical matters of interest, common to the

constituents, were discussed. Technical Co-ordination Committee meetings preceded

the WRP Committee meetings. Important decisions taken in the meetings are given

below:

The 10th WRP Committee meetings was held on 30th May 2009 at Diu

• ULDC project was under extended AMC period up to 31.05.2009 and there was

a need for going in for a comprehensive Long Term Service Agreement

(LTSA). M/s GE had submitted their offer to take up AMC which broadly

covered the scope of SCADA / EMS / DTS software as well as hardware at ten

control centers commissioned under the ULDC project. It was agreed to assign

the maintenance of sophisticated load dispatch system to OEM so that Real

time Data availability by interrupt free maintenance of LD equipment is

ensured being utmost important for grid operation. The WRP Committee

agreed for LTSA through OEM route and that LTSA be taken up with M/s GE

for five years at about Rs. 32.5 crores. Further replacement action for the new

system should be initiated before the end of three year period so that the new

system could be in place by the end of the LTSA period.

• The transmission system associated with Tilaiya Ultra Mega Power Project

(4000 MW) in Jharkhand, Nabinagar (1000 MW) of Railways and NTPC, Barh-

II (1320 MW), Rihand-III (1000 MW), Vindhyachal-IV (1000 MW) and Mauda

(1000 MW) of NTPC, and IPPs in Jharkhand, Orissa, MP, Chhattisgarh, and

Maharashtra were discussed and identified in 28th meeting of the Standing


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Committee on Power System Planning in WR .The transmission scheme were

identified in four groups, viz. (i) generation specific, (ii) system strengthening

common for WR and NR, (iii) system strengthening for WR and (iv) pooling

stations for IPPs in Orissa. WRP Committee agreed to the scheme and stressed

that the actual programme with each of the projects, once finalized, will be

brought forth in the Standing Committee meeting and to WRPC meeting. Also,

any change in the transmission scheme, if any, subsequent to discussion in other

region, will have to be brought to the notice of WRP Committee for its

approval.

• WRP Committee approved the cost estimates of Rs 5.16 crores towards

extending the data communication link from Raipur to Bhilai for pooling in

regional system.

• WRP Committee agreed to the transmission scheme connected with

vindhyachal pooling station and phasing of transmission work as below :-

a) When the initial unit at Vindhyachal stage-IV and Rihand-III generation are

commissioned they could be connected to Vindhyachal Pooling point and the

Vindyachal Pooling-Satna-Gwalior 765 kV link be charged at 400 kV level.

b) LILO of Vindhyachal- Jabalpur 400 kV D/C at Sasan.

c) the Vindyachal Pooling-Satna-Gwalior link can be charged at 765 kV level

along with interconnection of Sasan-Vindyhachal 765 kV S/C.

d) After charging at 765 kV level the LILO of Vindhyachal – Jabalpur 400 kV

D/C line at Sasan could be disconnected with suitable switching arrangements

at Sasan 400 kV switchyard to meet its starting power requirements in future.

• Clause 21(4) of Central Electricity Regulatory Commission (Terms and

Conditions of Tariff) Regulation, 2009, which came into force w.e.f. 1.04.2009,

envisaged that in case of fuel shortage in a thermal generating station, the

generating company might propose to deliver a higher MW during peak-load

hours by saving fuel during off-peak hours. The concerned Load Despatch

Centre may then specify a pragmatic day-ahead schedule for the generating


27

station to optimally utilize its MW and energy capability, in consultation with

the beneficiaries. Average Declared Capacity i.e. DCi in such an event shall be

taken to be equal to the maximum peak-hour ex-power plant MW schedule

specified by the concerned Load Despatch Centre for that day.” WRPC

decided following methodology for computation of payment of capacity

charges for thermal generating station in case of fuel shortage:

a) Peak Hours would generally be worked out by taking into regional load of

previous days or similar day of the previous week.

b) It would be of continuous 5 Hrs. (20 time blocks of 15 minutes)

c) The entire year will be divided in two seasons i.e. April to September as

summer and October to March as winter season.

d) Peak Hours during the month of April to September- 1800 Hrs to 2300 Hrs.

e) Peal Hours during the month of October to March – 1700 Hrs to 2200 Hrs.

f) DCi will be taken equal to maximum ex-power plant MW schedule specified

by the WRLDC continuously during the above defined peak hours for that

day

• WRP committee agreed to Installation of 1 x 125 MVAR bus reactors at Rajgarh

sub-station.

11th WRPC meetings was held on 25th September 2009 at Raipur

• The WR Power Committee approved the implementation of WAMS Project in

WR with TCS, IIT Bombay & Tata Power Company limited as consortium

partners and repayment of the loan from CSIR through UI cap fund. The

estimated cost of the project is Rs. 16.75 Crores. POWERGRID share of total

estimated cost of the project is Rs. 8.76 Crores to be met through UI cap fund.

The POWERGRID Share of project cost is for installation of PMUs,

Hardware/software at WRLDC etc. The data generated by PMUs shall be

available at WRLDC and shall be used by the WRLDC for grid operation as

and when they are commissioned. CSIR shall provide soft loan at an interest


28

rate of 3% for implementation of the project, which shall be repaid over a

period of ten years in annual installments. The Project completion time has been

envisaged as two years for development followed by one year for performance

monitoring. Balance amount of the project cost (Rs 7.99 Crs) would be given by

CSIR to IITB as grant and as loan to TCS and Tata Power. The total project

cost of Rs. 16.75 Crs shall be shared by PCGIL – 8.76 Crs, TCS- 3.77 Crs,

Tata Power, 1.44 Crs. and IIT-B- 2.77 . The main features of the project are

as follows:

(i) Installation of PMUs (Phasor Measurement Units) at around 25 to 30 locations

in Western Region Grid. The data from PMUs shall be acquired at Western

Regional Load Despatch Centre (WRLDC)

(ii) Development of software functions using PMU data.

• Transmission system associated with IPPs located in Orissa, Jharkhand, West

Bengal, Madhya Pradesh and Chhattisgarh, Vindhyachal-IV (1000MW) and

Rihand-III (1000MW) generation projects of NTPC and Mauda (2X500 MW)

generation project of NTPC , which were finalized by the Standing Committee

on transmission planning in Western Region were discussed and WR Power

Committee with a broader approach and in the interest of building up of strong

National grid network gave the concurrence for implementation of the proposed

transmission schemes

• As per the clause 9 of Central Electricity Regulatory Commission (Unscheduled

Interchange charges and related matters) Regulations, 2009, all payments on

account of UI charges including additional UI charges levied under the above

Regulations and the interest received on late payment thereof shall be credited

to a Fund called the “Unscheduled Interchange Pool Account Fund”,

Accordingly from 1st April’2009 onwards the surplus amount generated through

the interest earned through deposit amount for UI in IDBI bank and the residual

interest after payment to UI interest receivables will be kept in the

“Unscheduled Interchange Pool Fund”.


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Member Secretary, WRPC stated that during TCC meeting held on 24th September

2009, Gujarat, MP, Chhattisgarh and Maharashtra had suggested that planned outages

of 500 MW units should not be taken in the months of October to March of the year

and for the current year.

• The WRP Committee deliberated the issue relating to the power scenario in the

Western Regional grid and endorsed the following action plan recommended by

TCC on 24.09.2009: -

(i) The expected power deficit of Western Region 5500-7600 shall have

to be managed through the requisite load shedding and by

implementing distress load shedding plan in the right earnest and as

recommended by WRLDC.

(ii) AUFLS relays should be ensured to remain in operating condition

and provide load relief as per the expected quantum.

(iii) Planned outages of 500 MW units should not be taken in the months

of October to March of the year

The 12th WRPC meetings was held on 16th January 2010 respectively at Vadodara

• WRPC was informed of successful completion of PSS Tuning activity for WR

under Phase I, in which 12 units for PSS Tuning, namely two units each at Dahanu,

Wanakbori, Nasik, Korba West, Satpura and NTPC Korba were identified was

successfully completed. Further, 14 Units namely three units at Parli, three at NTPC

Korba, four at SGTPS Birsingpur, one at Chhattisgarh and three at Gandhinagar under

PSS Tuning for Phase-II in Part I were also identified and the tuning for six units

namely three units each at Parli and Korba NTPC had already been successfully

completed. In the month of Nov. 2009, PSS tuning of generating units at SGTPS

Birsingpur Unit No. 1 to 4 (210 MW each) and Korba (West) unit No. 2 (210 MW)

was carried out successfully.

• WRPC Committee observed that under the prevailing scenario, the excess

injection of power in the grid or excess drawl by the neighboring regions viz.


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NR and ER were the contributing factors for causing network congestion

following decisions were taken to ease congestion

a) The progress of ongoing intra-regional and inter-regional transmission

lines under construction shall be discussed and reviewed on quarterly

basis by TCC.

b) PGCIL shall carry out study to access the requirement of additional

inter-regional link

• Considering the importance of timely completion of on going transmission

network etc. the WRPC recommended that progress of intra-regional and inter-

regional transmission lines under construction in the region may be discussed

and reviewed on quarterly basis by TCC in a separate meeting. The meeting

shall be convened by Member Secretary, WRPC with representatives from State

TRANCOS, PGCIL and agencies executing transmission schemes in WR

through IPTC. The outcome of the same will be placed in TCC/WRP

Committee meeting for further deliberations.

• Due to failure of communication link between RLDC and SLDC, it became

difficult for SLDC to assess/monitor their real time drawal. The matter was

deliberated and WRP Committee decided that PGCIL will address the issues

concerning frequent failure of communication between RLDC and SLDC

leading in interruption of real time data communication to SLDC. Also, PGCIL

will discuss the matter with the supplier to check the feasibility of providing an

additional port in the gateway for data communication to SLDC in respect of

substation with automation.

• Budget / Revised estimate of WRPC secretariat for the year 2009-10 & 2010-

11. WRP Committee approved revised budget estimate for the year 2009-10

and proposed budget estimate for 2010-11 as indicated below:

Revised Budget Estimate for the year 2009-10 : Rs. 321 Lakhs

Proposed Budget Estimate for the year 2010-11: Rs. 321 Lakhs


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6.2 MEETINGS OF OPERATION & CO- ORDINATION COMMITTEE

The Operation & Coordination Committee consisting of System Operation Engineers

of constituent State Electricity Utilities, WRLDC, NTPC, PGCIL, Nuclear Power

Corporation, Tata Electric Cos., Reliance Energy Ltd., Torrent A.E. Company, NCA

etc. reviews the system operation and prepares monthly schedules. The Committee met

regularly every month and dealt with the following activities:

• Reviewing the schedule v/s. actual generation of various power stations, drawn

up in the previous month.

• Estimating the availability of power and energy from each power station and

demand of each State for the current and next month.

• Drawing up coordinated maintenance schedule for generating units and major

transmission lines etc.

• Reviewing norms for the system operational discipline to be observed by WR

constituents.

• Reviewing the operation of Automatic Under-Frequency Relays.

• Discussing system occurrences, if any, during the previous month and

reviewing the programme of implementation of the preventive measures.

• Any other specific issues concerning grid operation.

Important decisions taken in the Operation & Coordination Committee meetings

are given below

• Consequent to Commissioning of 400 kV Kansari-Kankroli D/C line in the

event of tripping of 400 kV Kansari-Soja line to avoid tripping of other 220 kV

feeders to Kansari committee suggested following measures

a) Diverting more power on NR-WR HVDC link

b) Load shedding at Kankroli

c) Opening one of the Feeder of 400 kV Kansari- Kankroli D/C


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• High voltage Problem at Sipat was deliberated and Committee observed that

automatic switching of unit aux. on station transformer in the event of unit

transformer tripping is a general practice and advised NTPC to approach suppliers of

scheme and find out solution so that 5% voltage restriction for switching is removed.

NTPC agreed to do so.

• It was agreed that all the constituents shall ensure availability of UFRs at

prescribed settings.

• Committee agreed to the needs that planned maintenance be carried out in

accordance with the recommendation of the Kukde Committee. It was stressed that the

constituents should adhere to the planned outage program as already approved. Also,

the progress of work should be closely monitored and time frame should be maintained

as recommended by Kukde Committee.

• The OC sub-Committee noted that Cabinet Sectt. have requested Central Nodal

Ministries / Departments to draw Schedule of Review of Crisis Management Plan

and draw up a schedule of mock drills to verify preparedness for the year 2009-10

• The OCC committee noted the following schedule for implementation of only

restricted governor operation in various types of thermal and hydro units:

Type Category To be implemented by

Software based EHG

system

1.03.2010 KWU & LMZ turbines

for thermal sets of 200

MW and above Hardware based EHG

system where boiler

controls are in “ Auto”

1.06.2010

Hydro units of 10 MW

and above

- 1.03.2010


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• Trial operation of the generating units ready for FGMO in WR may be carried out

on 02.04.2010

• The Sub-Committee discussed Full load testing of 765 kV / 400 kV

transformers at Seoni S/S and it was agreed that Powergrid may test full

load capacity of the transformers. However, adequate contingency measures

in the event of tripping of transformers shall be taken by

WRLDC/POWERGRID prior to the commencement of the testing so as to

ensure uninterrupted grid operation during the testing period.

6.3 MEETINGS OF COMMERCIAL COMMITTEE

During the year 2009-10, three meetings of the Commercial Committee of WRPC were

held to discuss and resolve commercial matters. The Committee discussed various

commercial issues and also reviewed the payment of weekly UI and reactive energy

charges etc. The Excerpts of the decisions taken in the meetings are:

52nd Commercial Committee meeting held on 9th April 2009, Mumbai

Commercial Committee had decided that the scheduling, monitoring etc. in respect of

Sugen Power Station will be carried out by SLDC, GETCO in line with CERC order

dated 7th May 2008. While granting the open access to Sugen Power station, SLDC,

GETCO, seeks clearance from WRLDC on day-to-day basis. It was noted that

considerable CTU network is used for evacuation of Sugen power and as such it was

necessary for SLDC, GETCO to ascertain if there is any congestion in CTU network.

Committee was requested to consider WRLDC's submission for reviewing the earlier

decision taken during 50th CCM as there is an exit way provided by CERC in case of

any difficulty faced by scheduling agency or RLDC. it was decided that scheduling,

monitoring, accounting etc. to be continued with SLDC, GETCO and in case of any

transmission constraints; generation at Sugen power station should be suitably

regulated.


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• In term of Central Electricity Regulatory Commission (Terms & Condition of

Tariff) Regulation, 2009, the monthly Energy account (REA) issued by RPC

shall also include a statement specifying the ratio in which transmission charges

for interstate transmission system for that month are to be shared by

transmission users in accordance with regulation 3.3. Also, the bill for

transmission charges (inclusive of incentive) for transmission charges for a

month should be raised by the transmission licensee based on its estimate of

Transmission System Availability Factor (TAFM) for the month and

adjustment, if any, has to be made on the basis of TAFM to be certified by the

Member Secretary of WRPC within 30 days from the last day of the relevant

month. Further as per Clause-32 (3) of Central Electricity Regulatory

Commission (Terms and Conditions of Tariff) Regulations, 2009, the monthly

regional energy account issued by Member Secretary of the Regional Power

Committee should also include a statement specifying the ratio in which

transmission charges for the month are to be shared by the transmission users in

accordance with regulation 33. Accordingly it was agreed that that PGCIL

would make available the details of outages (certified by WRLDC) to all the

beneficiaries by 10th of the following month. Concerned beneficiaries, after

examining these details, should furnish their comments/observations, if any, to

WRPC by the 20th of the following month. In case of non-receipt of the same by

this time period, it will be taken, as no comments. Member Secretary, WRPC,

will certify the TAFM accordingly. PGCIL would raise the transmission

charges bill based on the REA and constituents will make the payment

accordingly.

• In term of Clause 21(4) Of Central Electricity Regulatory Commission (Terms

And Conditions Of Tariff) Regulation, 2009, “In case of fuel shortage in a

thermal generating station, the generating company may propose to deliver a

higher MW during peak-load hours by saving fuel during off-peak hours. The

concerned Load Despatch Centre may then specify a pragmatic day-ahead

schedule for the generating station to optimally utilize its MW and energy

capability, in consultation with the beneficiaries. Average Declared Capacity


35

i.e. DCi in such an event shall be taken to be equal to the maximum peak-hour

ex-power plant MW schedule specified by the concerned Load Despatch Centre

for that day.” following was decided for computation of payment of capacity

charges for thermal generating station:

b) Peak Hours would generally be worked out by taking into regional load of

previous days or similar day of the previous week.

c) It would be of continuous 5 Hrs. (20 time blocks of 15 minutes)

d) The entire year will be divided in two seasons i.e. April to September as

summer and October to March as winter season.

e) Peak Hours during the month of April to September – 1800 Hrs to 2300 Hrs.

f) Peal Hours during the month of October to March – 1700 Hrs to 2200 Hrs.

g) Dci will be taken equal to maximum ex-power plant MW schedule specified by

the WRLDC continuously during the above defined peak hours for that day

53rd Commercial Committee meeting held on 8th September 2009 at , Mumbai.

• Automatic Meter Reading (AMR) solution developed by M/s BPL for

downloading and transmitting the data from remote locations to RLDCs having

main feature of automatically reading from the meter and transmitted to RLDC

was deliberated and the committee members unanimously opined that the above

project may be initially taken at few 3 or 4 locations in the Western Region free

of cost and based on the experience the decision for implementing the same for

all locations will be taken later on, Asoj, Koradi or Kolhapur, Korba(W) and

Bina or Bhopal locations can be initially taken up by M/s BPL to start the

project.

54th Commercial Committee meeting held on10th Dec. 2009 at Mumbai

• The Commercial committee deliberated the existing practice followed in WR

for Utilization of Un-requisitioned power by constituents of WR from NTPC

power stations in WR and its scheduling within the region in detail and


36

suggested that in view of observations made by WRLDC, the matter may be

put up to WRP Committee in its ensuing meeting. However, till such time the

present methodology for scheduling of un-requisitioned power from NTPC

station in WR to the deficit beneficiaries of WR may be continued.

• In accordance with the directions given by the Hon’ble Commission in the order

dated 31.07.2009 in the petition No. 64/2008 and 67/2008, Transmission

charges for use of GETCO transmission system for conveyance of central sector

power to DD and DNH for the period 1.04.09 to 31.03.2010 WRPC Secretariat

had worked out the transmission charges payable to GETCO for conveyance of

Central Sector power to DD & DNH for the period 1.04.09 to 31.03.2010. The

total charges for the year 2009-10 in respect of DD worked out to Rs. 173.41

Lacs whereas in respect of DNH it is Rs. 380.30 Lacs. . The same have been

implemented in the REAs w.e.f. the month of Sept-2009 and for the past period

i.e. April-09 to August-09 and the REAs have accordingly been modified.

6.4 MEETINGS OF PROTECTION COMMITTEE

The Protection Committee constituted by WRP Committee met four times during the

year 2008-09 to review the performance of the protective relaying schemes in the

context of system occurrences which had taken place in the Western Region and to

evolve corrective / preventive measures to enhance grid security. Major

recommendations and issues discussed during above meetings are given below:

105th Protection Committee Meeting held on 18th June 2009 at WRPC Mumbai:

The Committee discussed the system occurrences that occurred in the WR grid during

the period January 2009 to March 2009.

In regards to the system disturbance at 400kV Kharghar S/S, in MSETCL system on 27-

01-2009, Committee observed that tripping of Main bus-II was in order, but operation of


37

Main bus-I was undesirable and felt that the auxiliary contact of the TB isolator might

have operated (mal operation due to interconnection problem) resulting in operation of

Zone-I Bus bar protection. MSETCL, representative told that the high impedance Bus

Bar protection schemes are being replaced with modern numerical Bus Bar protection

schemes at important S/S’s, in a phased manner.

In regard to the system disturbance due to operation of LBB relay at 400 kV Khedamara

S/S in CSPTCL system on 03-02-2009, Committee felt that the 86 relay might have

remained in stuck condition after extending the tripping command to the breaker for

about 200msec. The LBB scheme detected this condition as the stuck breaker condition

and operated. Committee recommended for early replacement of the existing scheme by

phase segregated scheme.

In regards to the system disturbance due to tripping of 220kV Kim-Zagadiya line No. 1

& 2 on Y ph. over current at Kim S/S at 220 kV Kim S/S in GETCO system on 09-02-

2009 leading to tripping of generators at Utran and TPGL, due to non availability of

evacuation, Committee felt that with limitations on the evacuation of power due to

outage of 220kV Kim-Vav 1 & 2 lines, the PS settings of the 220kV Kim-Zagadiya

lines should have been raised to 100% before the outages and also corrective actions

would have been taken to restrict the generation at TPGL, for avoiding the occurrence.

In regards to the system disturbance at 220 kV Uran S/S in MSETCL system on 26-

03-2009, due to busting of the Y-ph line PT resulting in operation of Zone-I bus bar

protection, Committee felt that multiple faults took place over a span of short time at

different locations. The tripping of Bus bar zone1 is in order for a PT fault, which is

covered in this Bus zone. For a transient Y phase to Earth fault on the 220kV Uran-

Apta#2 line the tripping at Apta end on backup protection ahead of DPS zone 2 is

undesirable, and as such the DPS scheme at Apta end should be tested thoroughly. The

backup relay settings of 220kV Uran-HOC-Apta#1 should be reviewed and time

coordinated with the zone-2 timings of the DPS.


38

In regards to system disturbance due to operation of the 220kV Main Bus bar-I

protection scheme, at 220 kV Khaparkheda S/S in MSETCL system on 27-03-2009

Committee observed that the operation of Main Bus 1 Bus Bar protection is in order.

However it was felt that the cause of the bus fault was because of non adherence to the

standard S/S maintenance practices. Maintenance of S/S equipments should be done

strictly as per schedule and earth wire shield between gantry nos 39 & 40 should be

provided at the earliest.

In regards to system disturbance , due to operation of 220kV Main Bus-1 at 400 kV

Chandrapur S/S in MSETCL system on 28-03-2009, Committee observed that the

operation of bus bar protection for TBC (Aux. Bus) and 220kV Main Bus-1 was in order.

However the trippings of 220kV Chandrapur-MIDC and 220kV Chandrapur-Warora

ckt.1 from remote end on DPS Zone 1 is undesirable and the DPS is overreaching.

Committee recommended for through testing of the DPS schemes. MSETCL

representative told that the DPS schemes are proposed to be replaced with numerical

relays.

In regards to the system disturbance, due to multiple tripping of lines and generating

units at KLTPS, SLTPS and ALTPS at 400 kV Chorania S/S in GETCO system on 30-

03-2009, Committee observed that the 400kV Asoj-Chorania line#1 might have tripped

in Zone 1 due to overreach. The power swing blocking and over voltage protection might

have operated due to a sudden throw off of load due to the line trippings.

In regards to the system disturbance due to operation of 220kV Zone-1 Bus Bar

protection at 220 kV Mehsana S/S in GETCO system on 14-01-2009, Committee

observed that the operation of Zone-1 Bus Bar protection scheme was in order.

Committee also felt that regular maintenance/ tightening of the wirings in the relay

panels should be carried out.


39

106th Protection Committee Meeting held on 1st and 2nd September 2009 at WRPC

Mumbai.


the period April 2009 to June 2009.

In regards to the system disturbance due to non operation of the ABB make RADSS Bus

Bar protection scheme, resulting in tripping of lines from remote ends at 220 kV Tapper

S/S in GETCO system on 02-05-2009, Committee observed that the fault was sensed and

cleared by the remote end relays of the lines connected to the Bus in zone-2, suggesting

that the fault was fed for the zone 2 timings. Further though the fault was of highly

resistive in nature (which would have been confirmed if the fault currents recorded by

the DRs of the remote relays would have been made available), the insensitivity of the

ABB make RADSS Bus Bar Protection scheme to such type of faults needs to be taken

up with the manufacturer.

The Committee further observed that while documenting standard operating procedures,

which are in process, the education of operating staff should be included so as to avoid

such man made mistakes.

In regards to the system disturbance due to non operation of the Areva make numerical

Bus Bar protection scheme because of wrong wirings at 220 kV Wagra S/S in GETCO

system on 31-05-2009, Committee felt that wirings should be checked at the time of

initial commissioning/testing of the Bus Bar protection scheme to avoid such avoidable

failures.

In regards to the System disturbance due to operation of LBB of the T/F-1, while

charging the 220/66 KV 100 MVA T/F -1 on 96 relay at 220kV Vav S/S in GETCO

system on 23-06-2009, Committee felt that the inrush current sustaining for 10cycles is

not a good sign from the point of view of healthiness of the transformer as per the

records of the DR recorded by the relay. Further it was also felt that the transformer

Breaker should have tripped through the TC-2, in the event of failure of the TC-1.


40

In regards to the system disturbance due to operation of the Bus Bar differential

protection of 132 kV Bus A at Sikka TPS in GSECL system on 04-06-2009, Committee

observed that the tripping of feeders connected to Bus-A on operation of the Bus Bar

protection is in order. However tripping of 132kV Dhrol and 132kV Naghedi lines

connected to Bus-B from remote ends in Zone 3 timing is highly undesirable for a Bus

fault of transient nature and in view of the normal test results of the Bus Coupler breaker

timings. It was also pointed out that if PMU data comes into the system such failures

could be precisely detected and rectified.

In regards to the system disturbance due to operation of 220 KV Main-I Bus-bar

protection scheme at 400 KV S/S Nagda in MPPTCL system on 23-05-2009, Committee

observed that the operation of the Bus Bar protection is in order. However the non-

tripping of 220kV Nagda-Ratlam-I feeder at local end and tripping of this feeder from

remote end in Zone 2 is incorrect. The Circuit Breaker control circuit of this feeder at

Nagda end needs to be thoroughly checked.

In regards to the system disturbance due to operation of the 220kV Bus bar Zone-

2protection at 220kV GTPS Uran S/S in MSETCL system on 19-04-2009, Committee

observed that with the operation of the Bus Inter-connector and Bus Zone-2 protection,

all the 220kV feeders connected to the Bus –I should have also tripped (due to clubbing

of Bus Zone-I & II), thereby isolating the fault being fed from remote end sources and

local sources connected to Bus-I. Due to failure of DC supply meant for isolator logic

of GT unit 5,6,7 & 8 and in view of the Bus Inter-connecter operated (thereby blocking

the Bus Coupler trip), the fault was being fed by these generators from Bus-I and from

Bus-II through the Bus Coupler till the backup protection of the GTs cleared the fault.

However the tripping of 220kV Uran-Apta-II in Zone 2 at Apta end is undesirable. The

trip control circuit of this feeder at Uran end should be checked thoroughly in view of

the CB timing test results of the CB were in order. Also the control circuit of extension

of Bus Bar trip command to all the feeders needs to be checked.

In regards to the system disturbance due to snapping of B phase jumper of 220kV Bus

Coupler bay from isolator end at 400kV Karad S/S in MSETCL system on 19-05-2009,

Committee observed that though the fault was out of zone fault for Bus Zone-1, the fault


41

would have been sensed in the Bus zone-II by the Bus Bar protection scheme. The matter

may be taken up with M/s ABB for not sensing the fault, in view of the fault contribution

recorded by the remote end DRs. Also had the earth fault protection been provided to the

Bus Coupler, the fault would have got isolated. Committee also felt that tripping of

400kV lines and 220kV lines from remote ends in Zone 2 is undesirable and ICTs should

be provided with directional back up protection on HV and LV sides.

In regards to the system disturbance due to operation of 220kV Bus Bar-I differential

protection at 2x220MW KAPS ATPS in NPCIL system on 02-04-2009, Committee felt

that the clamping arrangement of Bus post insulator as described by NPCIL

representative is as per the standard practice. The Bus post insulators might have failed

due to mechanical stress and aging of the insulators hence special attention to condition

monitoring of the older equipment needs to be done. Also, NPCIL may examine the need

of increase in number of supports.

In regards to the system disturbance due to operation of Bus-bar protection of Bus-2 at

400kV Jabalpur S/S in PGCIL system on 12-05-2009, Committee observed that the

operation of Bus Bar protection scheme is in order. However the trippings of 400kV

Vindhyachal-Jabalpur#2, 400kV Jabalpur-Itarsi#1&2 on operation of Main-I/Main-II

protection and sensing the fault in reverse direction is incorrect. Also operation of over

voltage stage –I protection of 400kV Vindhyachal-Jabalpur # 3 & 4 and Jabalpur-Itarsi

#3 & 4 lines is undesirable in view of increase in loading on these feeders due to

tripping of other evacuating circuits.

In regard to the system disturbance due to the mal-operation of Bus-bar protection

(because of scheme wiring problem) for through fault at 400kV Rajgarh S/S in PGCIL

system on 17-06-2009, Committee observed that necessary corrective actions have

already been taken to avoid the undesirable tripping. However PGCIL may take up the

matter with the manufacturer for necessary corrections in the Bus Bar differential

scheme.


42

107th Protection Committee Meeting held on19th and 20th November 2009 at

Lonawala.


the period July 2009 to September 2009.

In regards to the system disturbance due to operation of LBB protection of Generator

Transformer Unit # 2 at Wanakbori TPS in GSECL system on 18-07-2009, Committee

in general felt that the suggestions needs to be looked at depth and may be taken up while

reviewing the protection manual. However the control circuit needs to be checked during

the routine testing of these relays.

In regards to the system disturbance due to operation of LBB Relay of 400kV Indore-Nagda

Feeder at 400 KV S/S Indore in MPPTCL system on 19-04-2009, Committee felt that the

operation of LBB is undesirable. Sensing the fault at Nagda end (400kV Indore-Nagda

feeder) by the distance protection in Zone-2 indicates that the D/T was not sent from Indore

end and/or not received at Nagda end. Committee further recommended for draining of

moisture regularly for pneumatic breakers, since this leads to corrosion of the operating

mechanism resulting in delayed operation/clearing of fault. Committee also felt that due to

non availability of the SOE and DR records it is very difficult to arrive at any conclusion and

suggest remedial measures and insisted that utilities should make available such records

along with the disturbance reports.

In regards to the system disturbance due to operation of 400kV Bus-Bar differential

(Zone 1, Y-ph) protection at 400kV Satpura S/S in MPPGCL system on 27-08-2009,

Committee observed that the operation of Bus Bar differential protection was in order.

However tripping of 400/220kV ICT on instantaneous O/C is undesirable. The need for

providing/enabling the instantaneous/High set feature of O/C, E/F (backup protection)

may be reviewed during the protection manual review.

In regards to the system disturbance due to operation of the Bus Bar Protection Scheme

at Korba STPS in Chhattisgarh system on 13-09- 2009, Committee observed that the

operation of the Bus Bar protection was in order, however due to tripping of 400kV


43

KSTPS-Bhilai#2 from Bhilai end on receipt of spurious PLCC signal, aggravated the

situation. Committee felt that a statistical data of mal operation of PLCC schemes of

various manufacturers needs to be compiled at the RPC level and requested constituents

to submit the data of PLCC (along with make, type & date & time of operation) mal

operations for the last one year to WRPC.

Also Committee felt that the periodicity of thermovision scanning be raised and this

activity be closely monitored at important S/S’s particularly at the Generating Stations.

In regards to the system disturbances due to operation of the Bus Bar protection of Bus

Coupler 1 (between Bus-1 & Bus-2) and the LBB trip protection relay K96 respectively

at 400 kV VSTPS Vindhyachal S/S in NTPC system on 03.10.2009 and 04.10.2009,

Committee felt that the operation of protection scheme on 03.10.09 was in order.

However necessary steps are required to be taken to avoid accumulation of water vapors

on the S/S yard equipments from the near by cooling towers so that such incidences

could be avoided in future. Also the recommendations of the report of the “Study Group

on the disturbance of 22.07.08 at Vindhyachal STPS”, circulated vide letter No.

WRPC/Prot./Vindya/2008-09/5891 Dtd.03.06.09 be followed and the compliance of the

same may be submitted at the earliest. NTPC representative intimated that

recommendations at paras (ii),(iii),(iv) &(v) of the report of the “Study Group on the

disturbance of 22.07.08 at Vindhyachal STPS”, have been implemented and the

recommendation at (vi) would be complied soon. Committee further felt that the

occurrence of 04.10.09 due to operation of LBB protection seems to be logically in

correct, since taking the feeders into service connected to the Bus section without

resetting the LBB relay (which was operated on 03.10.09), is impossible.

108th Protection Committee Meeting held on 25th and 26th March 2010 at Koradi

Nagpur.


the period October 2009 to December 2009.


44

In regards to the system disturbance due to operation of Local Breaker Back-up (LBB)

protection of GT-5 at Ukai TPS in GSECL system on 17-10-2009, Committee observed

that the operation of LBB operation due to delayed opening of Y pole and operation of

the low forward power relay is in order. The existing LBB scheme having minimum

current setting of 0.2A, be replaced by LBB scheme having minimum setting of less

than or equal to 0.05A for generator units. Committee felt that the LBB timings for

generators and PDR be kept 200msec and 150msec respectively, since time

discrimination of 50msec is available.

In regards to the system disturbance due to operation of Bus Bar protection of Bus-I at

400kV Choraniya S/S in GETCO system on 29.11.2009, Committee observed that as

discussed in the past, Tan-delta alone couldn’t ascertain the health of the CT. However

trend (deterioration in Tan-delta) of the Tan-delta measurements can give a clue about

the health of the CT. The DG analysis is a comprehensive tool to decide the health of

CT, hence constituents may adopt online DGA and Tan-delta measurements at critical

locations, since these online measurement kits are available in market.

In regards to the system disturbance at 400 kV S/S Indore in MPPTCL system on 22-10-

2009, Committee felt that the CT failure of Jetpura line might have initiated from the line

side thereby resulting in a through fault and as seen from the DR the fault was isolated by

DPS in less than 80msec. Further Committee appreciated supplementing of the DR reports

along with the occurrence report and requested the members of the sub-Committee that all

the major occurrences under Item No. 2, be supplemented with relevant DRs, so that the

analysis/review of the protection schemes/settings becomes easier by correlating the recorded

data with the studies data.

In regards to the system disturbance due to failure of B phase CT of 220 kV Bus coupler

bay at 220kV Parli S/S in MSETCL system on 29-11-2009, Committee felt that thermo

vision scanning be carried out regularly at old S/Ss where the equipments are old.


45

Study Group report on system disturbance at 400 kV VSTPS Vindhyachal S/S in

NTPC system on 22-07-2008

A study group comprising of members from WRPC, WRLDC, VSTPS, Powergrid,

GSECL and MSETCL was formed by Member Secretary, WRPC to look into the matter

in detail and analyze the incidence and come up with remedial measures to avoid

reoccurrences of such incidence

The findings and recommendations of the Study Group is as follows,

(i) There is a need for proper monitoring of the S/S equipment healthiness. Best

practices should be adopted. Different utilities follow different practices. A common

minimum maintenance practice, philosophy and periodicity of testing and details of

tests carried on EHV system equipments should be standardized. In particular DCRM,

Dew point measurements, overhaul of CB operating mechanism etc should

compulsorily be carried out at regular intervals. Protection Committee Meeting (PCM)

forum of WRPC may bring out a common minimum maintenance requirement of EHV

system equipments for adoption by utilities.

(ii) Whenever a timing discrepancy is observed in the CB during testing, it should

be attended immediately.

(iii) DPS of Vindhyachal-Satna #1, and Vindhyachal-Satna #2 lines should be

thoroughly checked for mal-operation during this incidence at Vindhyachal STPS on

Zone-2.

(iv) Monitoring equipments such as Event Recorder, Disturbance Recorder, GPS

time clock are to be kept in working conditions. Effective measures needs to be taken

by stations for maintaining these equipments.

(v) During this disturbance efforts were made to save the two generating units by

transferring them to the healthy bus section, when the line breaker had developed

problem. During this process, a bus fault took place due to faulty breaker and resulted

in entire station tripping and also risked the N-E-W Grid. If instead of saving the two

units, the faulty element/section was isolated by opening the bus coupler immediately

(which would have tripped the two units), the damage would have been limited, most

of the generation would have been saved and N-E-W Grid would have been subjected


46

to lesser stress. Therefore the Study Group recommends that an action plan needs to be

developed by all Generating stations and EHV sub-stations to deal with the emergency

situations such that faulty elements/section should be taken out from grid as fast as

possible to avoid cascading effects.

(vi) Separate differential relays are used for protection of each zone, at Vindhyachal

STPP. This Bus Bar protection scheme should be replaced with numerical Bus Bar

protection at Vindhyachal STPP.

6.5 MEETING OF SYSTEM STUDY GROUP

System Study Group of WRPC, comprising the representatives from the constituents of

the Western region, conducted system studies and operational planning studies

concerning the Western Regional Power system. The System Study Group carried out

studies to finalize the requirement of HT shunt capacitor.

WRPC prepared the study cases for the 2008-10 conditions and the conducted studies

keeping the NR, ER and WR systems in synchronous mode as per present

interconnection conditions. The meeting of the Study Committee was held on 20th April

2009. Since there was no significant addition of EHV/HV shunt capacitors during 08-

09 and the EHV Shunt capacitor requirement targets finalized for 08-09 studies were

felt to be adequate hence the targets for the year 08-09 were retained for the year 09-10.

The targets for 09-10 were as below:

S. No Constituent Capacitor targets in MVAR

1 Gujarat 435

2 Maharashtra 375

3 Madhya Pradesh 110

4 Chhattisgarh 90

5 Goa 0

6 TPC 0

7 AECO 0

8 WR 1010


47

6.6 MEETINGS OF LGBR STUDY COMMITTEE

The report of Load Generation Balance covers the anticipated power supply position viz.

month wise station generation, total availability and requirement, anticipated capacity and

energy shortages of the constituents of the Western Region. The anticipated availability of

each constituent has been worked out taking into consideration of installed capacity, new

addition in generation, maintenance schedule, partial and forced outages etc. The LGBR

helps the constituents in initiating advance action for power purchase and for working out

load regulatory measures. During the year 2009-10, the LGBR Study Committee met on

12.06.09 for 1st quarterly review for the year 2009-10, on 11.09.2009 for 2nd quarterly

review for the year 2009-10, and on 11.12.09 for 3rd quarterly review for the year 2009-10

wherein maintenance programme for the Annual LGBR for the year 2010-11 were finalized.

The Committee met on 12.03.10 to discussed and finalized the requirement details for

the year 2010-11.

Special Meeting to discuss the technical details of the proposed Wide Area

Measurement Systems (WAMS):

A meeting was held on 17.9.2009 at WRLDC, Mumbai to discuss the technical

details of the proposed WAMS project The brief outcome of the discussions is as

follows:

a) MSETCL representative stated that Maharshtra is already implementing a

project of installing PMU / WAMS in their system.

b) GETCO, MPPTCL and CSPTCL representatives were of the view that the

implementation of WAMS should be done at a regional level as proposed by

POWERGRID.

c) So far as the proportionate sharing of the cost of Rs 8.76 cr by Maharshtra is

concerned, Maharashtra stated that they will not be able to share the same as

they are already implementing the WAMS project in their system.

d) Regarding installation of PMUs in MSETCL system under the proposed

regional WAMS project and utilization of the MSETCL installed WAMS PMU


48

data in Maharashtra system, MSETCL representative stated that they would

revert back.

e) Constituents suggested that the expenditure of Rs 8.76 cr for the above project

may be met from the UI cap fund as the project is for system improvement.

WRLDC clarified that this will be subject to the approval of CERC.

f) It was suggested to form a PMU study group at RPC level comprising of

representatives of Protection groups from all the constituents of WR, that will

look into the analysis of correct/incorrect operation of the protection relays

during line trippings and other grid disturbances using inputs from WAMS data

which is in milliseconds time frame, study of stability related issues by study

group etc. At present the data routing was envisaged at RLDC levels. Hence the

data routing should be such that the WAMS PMU data is available to the

Protection and Study groups both at the State as well as RPC level. The

necessary details of data routing to the SLDC/WRLDC/Protection and PMU

Study group can be finalized accordingly.

g) It was also suggested that Task force from the representatives of WR

constituents may be formed which would monitor the progress of the

implementation of the proposed WAMS project.

h) Constituents felt that the continuous real time data (24 x 7) should not be

provided in view of the commercial implications. POWERGRID representative

agreed to discuss the same with IIT-B and revert back. The data sharing by IIT-

B in the above pattern may be done during the project implementation period

only.

Meeting to discuses issues related to synchronization of first unit (330 MW) of

Mundra Thermal power station of M/s. Adani Power Ltd. and its connectivity to

the grid was held at WRPC office Mumbai on 9th April 2009

• The issues concerning synchronization of first unit of 330 MW of Mundra

Thermal Power Station along with its dedicated 400kV Mundra-Sami-Dehgam

transmission line with WR grid was deliberated where in the following was

agreed:


49

a) Initial synchronization of 330 MW 1st Unit of Mundra, TPS of Adani Power

Limited will be through 220 kV Mundra-Nani Khakhar line as this is the only

available link for start up power.

b) Thereafter 400 kV Mundra-Sami-Dehgam line will be charged as per the

charging instructions issued by the CTU (POWERGRID) in coordination with

WRLDC.

c) To enable initial synchronization through Nani Khakhar M/s. Adani Power

Limited (M/s APL) shall coordinate the activities with GETCO authorities in

consultation with SLDC, GETCO, Vadodara.

d) M/s. APL will ensure that all the requisite metering arrangements etc. are in

place before synchronization and connectivity of the lines with grid in

consultation with WRTS-II, PGCIL, Vadodara / WRLDC.

e) WRLDC pointed out that the SEMs (APEX meters of M/s Secure) presently

provided by M/s APL are not compatible with software available at WRLDC.

M/s APL was requested to ensure that compatible meters are provided before

synchronization. If needed, they may request WRTS-II PGCIL, Vadodara for

providing the required meters at Mundra end on payment basis. M/s APL also

to provide SEMs (4 Nos.) on 220 kV Mundra-Nani Khakhar D/C line.

f) M/s APL would confirm in writing the readiness of 400 kV Mundra-Sami-

Dehgam D/c lines after completing pending works.

g) M/s APL would ensure PLCC communication on Mundra-Sami-Dehgam

sections after getting clearance/approval for frequency from relevant authorities.

h) M/s. APL will take prompt action for providing speech, telemetry and data

communication to WRLDC in accordance with IEGC.

6.7 MEETINGS HELD DURING THE YEAR 2009-10

List of WRPC and other Committee Meetings held during the year 2009-10 is given in

Annexure - XXI.

* * * * *

6E- Chapter 2009-10-Final - Welcome to Western Regional Power …wrpc.gov.in/annualreport0910/chapter6.pdf · · 2011-03-02envisaged that in case of fuel shortage in a thermal generating

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