Status Grid Disturbance Report

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STATUS OF ACTION TAKEN ON RECOMMENDATIONS OF THE ENQUIRY COMMITTEE ON GRID DISTURBANCE IN NORTHERN REGION

ON 30th JULY 2012 AND IN NORTHERN, EASTERN & NORTH-EASTERN REGION ON 31st JULY 2012. (As on 22-03-2013)

S.No. RECOMMENDATIONS Action Taken

9.1.1

There is a need to review protection schemes. This

Committee concurs with recommendation of previous

enquiry committees that a thorough third party protection

audit need to be carried out in time bound manner. This

exercise should be repeated periodically and monitored by

RPCs.

Action: RPCs, CTU, STUs

Time Frame: 1 year

NR : PGCIL has completed protection audit of all 132 important substations/

switchyards in the Northern Region in various phases on 15th

November 2012. Gist is

given at Appendix-I.

WR: The audit of 137 out of 212 important substations in the Western Region has

been completed and audit in remaining sub-stations is likely to complete by April

2013. In Gujarat, the audit was completed by a third party earlier in 2010 itself and

all deficiencies rectified. In Maharashtra, audit of 90 s/s out of 119 S/s has been done

rest to complete by March-13. In MP audit of 11 out of 37 S/S have been carried out

rest to complete by April 2013. In Chhattisgarh audit of 9 out of 16 have been

completed rest to complete by March-13, Goa & UTs, the process of audit is being

finalized. 18 sub-station out of 31 sub-station belonging to PGCIL and NTPC has

been comleted and rest is likely to complete by Aril-13.

SR : Protection Audit have been completed for all 194 critical substations in the

region on 22nd

December 2012. Audit report circulated to all States and action plan to

was discussed in SRPC meeting held on 2nd

Feb-2013. As per the action plan the

corrective measures have been initiated and to be complete within time frame ranging

from 3 months to two years and total expenditure of around 158 Crores.

ER : Protection audit for 42 S/s of 400kV, 1 HVDC and 11 S/s of 220 kV completed

and report subted to RPC. DVC, West Bengal and Odhisha prepared action paln and

intitiated actions. Jharkhand and Bihar to prepare the action plan and has to started

work.

NER : In NER there are about 135 Nos. of substation and generating stations of

132kV and above voltage class. The protection audit was planned in consultation

with NERLDC, STU, CTU and Generating companies of NER. In February 2013, the

protection audit of all stations was completed as per schedule. The report on audit of

Protection system along with recommendations and implementation plan is likely to

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be submitted by March 2013.

9.1.2

Till protection audit is taken up, there is need to take

immediate review of zone-3 philosophy in particular.

Techniques are available to modify characteristics of the

relay so that it can distinguish between load encroachment

and faults. These techniques and other alternatives should

be explored immediately.

Action: RPCs, CTU, STUs

Time Frame: Immediate

Earlier, Zone-3 settings were not considered as part of the line loadability criterion.

However, after the grid disturbances, the Zone-3 settings have been collected and

analyzed to arrive at the safe line loading limits. In a meeting taken by Member (PS),

CEA with CTU and POSOCO on 26th

September 2012 regarding transmission line

loadability, loading limits of transmission lines on all India basis were finalized and

circulated vide letter dated 3rd

October 2012. The report contains Zone-3 settings as

well, wherever available. All concerned have been advised to check the settings

where indicated / intimate the settings where not available. It was also decided at the

meeting that Zone-3 settings need to be reviewed by POWERGRID in coordination

with STUs, Generators and POSOCO so as to avoid load encroachment.

POWERGRID has reviewed and verified all the implemented Zone-3 settings.

9.1.3

The application of synchro-phasor measurements from

PMUs should be explored for protection systems. There is

also an urgent need to deploy Special Protection System

(SPS) in critical transmission elements. Also, there is need

to make already approved SPS operational.

Action: RPCs, CTU

Time Frame: 1 year

As per information from CTU, NR 9 PMUs; SR 3 (+9 under implementation) PMUs;

ER 12 PMUs (under implementation) and WR 10 PMUs (+7 under implementation)

are functional.

Further, Unified Real Time Dynamic State Measurement (URTDSM) Scheme with

large scale deployment of PMUs is under CERC approval.

12 SPS of SR are already functional. 6 more SPS, are under various stage of

implementation. In NR & ER 3 SPS each and in WR 2 SPS are implemented.

9.1.4

A complete independent audit of time synchronization of

DRs, ELs and PMUs should be carried out.

Action: Generators, CTU, STUs.

Time Frame: 1 month

This also forms a part of the protection audit undertaken / to be undertaken by CTU /

STUs as per item 9.1.1 above.

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9.2.1

Frequency band needs to be further tightened and brought

close to 50 Hz. POSOCO may file an urgency application

in Supreme Court for early resolution of the issue in view

of the recent grid disturbances.

Action: POSOCO

Time Frame: 1 month

CERC has directed the Commission Staff vide its order dated 29.11.12 to consider

the POSOCO petition for further tightening of frequency band to 49.9 - 50.1. Hz. and

prepare a proposal for further action on the same.

Under active consideration of the Commission and involves examination by a

committee comprising CEA, CTU and CERC. Commission to take a view based on

recommendations of committee.

Committee expected to take about 4 weeks time and about another 8 weeks required

to amend the Regulations. (in about 3 months time) by June 2013

9.2.2

A review of UI mechanism should be carried out in view of

its impact on recent grid disturbances. Frequency control

through UI may be phased out in a time bound manner and

Generation reserves/Ancillary services may be used for

frequency control. Appropriate regulatory mechanism

needs to be put in place for this purpose. POSOCO should

take up the matter with CERC.

Action: POSOCO

Time Frame: 3 months

Regarding the Generation Reserves / Ancillary services, the petition for introducing

these services in the country was filed by NLDC with CERC on 29.11.2010. Against

this, CERC in its order issued on dated 20.07.2012 has directed its staff for

formulation of draft Regulations for Ancillary Services and CERC staff is working

on this proposal alongwith the proposal for amendment to the IEGC.

9.3

All STUs should immediately enable under frequency and

df/dt based load shedding schemes. Central Commission

should explore ways and means for implementation of

various regulations issued under the Electricity Act, 2003.

Any violation of these regulations can prove to be costly as

has been the case this time. RPCs need to take up the matter

for compliance. In case non-compliance persists, POSOCO

should approach Central Commission.

Action: STUs, RPCs, POSOCO


NR: status of functioning of Under-Frequency Relays (UFRs) and df/dt relays in NR

as per the information received from various constituents are as under:

1. In Delhi all 24 UFR and 13 df/dt realys are functional.

2. In UP out of total 148 nos of UFR only 58 are functioning. (18 nos. of UFR have

been procured and are being installed. 76 nos. of UFR are being procured and

expected with expected delivery upto May 2013)

3. In Punjab out of 31 nos of UFRs 05 are non-functional and out of 28 nos of df/dt

03 nos are non-functional (3 nos of UFR and 01 no. df/dt of have been made

operational. Information in regard to balance 02 nos of UFR and 02 nos of df/dt

is awaited)

4. In Haryana out of 28 nos of UFR and 6 df/dt relays, 9 UFR were found defective

5 UFRs made operational and for 4 nos. of UFR order has been placed for

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replacement.

5. In Rajasthan all 4 defective UFR out of 88 UFR, would be operational by 31-03-

2013.

6. In Himachal Pradesh all 3 UFR are operational one df/dt relay out of 3 is

defective which is being rectified.

7. J&K and Uttarakhand – status not submitted, matter has been taken up with

respective electricity departments.

8. Chandigarh has not submitted the self certification for its total 2 UFRs., matter

taken up with Chandigarh.

WR: Formed a committee to look into the matter of UFR and df/dt relay settings.

The committee has revised (increased) the load-relief to be provided by UFRs

keeping in view the voltage and frequency dependence of load.

SR: Data regarding status of functioning of UFRs and df/dt relays has already been

collected and sent to SRPC by PGCIL. It has been found that relays are available and

enabled at all substations except some lines (Tamilnadu - 8 locations, Karnataka -11

locations, Andhra Pradesh – 7 locations and one location each in Kerala and

Puducherry). Corrective action on deficiencies is in progress.

ER: UFR settings have been revised and made equivalent to those in NR and WR i.e.

48.8, 48.6 & 48.2 Hz and also finalized the quantum of load relief from each State of

ER. States have confirmed that all UFRs as per the scheme of load-relief decided by

ERPC are functional. A sub-group has been formed to carry out inspection of

healthiness of UFRs. The inspection is being carried out regularly. The subgroup has

been entrusted to carryout at least two inspections every month and submit the report

in monthly OCC meetings.

NER: The states in NER are understood to have submitted self-certification

regarding functioning of under-frequency relays. No df/dt relay is installed in NER.

POSOCO: Non-compliance of CERC regulations are being brought to the notice of

the commission. High level logic for an automated contingency load shedding

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protocol was circulated by POSOCO on 11th September 2012. Detailed logic for

implementation being worked out in consultation with the states. A Petition on UFRs

& df/dt relays was filed by NRLDC with CERC on 19th Sept, 2012.

As per record of proceedings of hearing held on 14.02.2013,

(a) All entities shall ensure healthiness of the defense mechanisms i.e. UFR, df/dt

relays etc at all the time;

(b) RPC secretariats shall monitor and ensure corrective actions within time frame;

(c) All entities, who have not submitted the information, shall immediately file

information, on affidavit with an advance copy to NRPC and NRLDC on or

before15.3.2013;

(d) NRPC shall take up the issue in the next NRPC meeting and submit the time

schedule for procurement/rectification of all the relays in the NR and submit

compliance report by 15.3.3013 as per Regulation 1.5 of the Grid

Code.

(e) NRLDC shall submit the operational report of the load relief obtained from the

under frequency relays to NRPC Secretariat and to the Commission by 22.3.32013;

and

(f) NRLDC and NRPC may file, any discrepancy detected on the submissions filed

by the respondents, on affidavit, with copy to the respondents, by 1.4.2013.

The Commission directed the officer in charge of State STUs and SLDCs, who have

not filed any response, appear before the Commission in next date of hearing to

explain the reasons for non-compliance of the Commission's directions.

The petition is listed for hearing on 9.4.2013.

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9.4 All out efforts should be made to implement provisions of

IEGC with regard to governor action. Central Commission

needs to look into ways and means to hasten

implementation of provisions of IEGC including that on

governor action. POSOCO need to take up the matter with

Central Commission.

Action: POSOCO


CERC in its order dated 31.12.2012 reiterated the need for compliance by generators

and directed as to why they may not be held responsible for non-implementation of

RGMO / FGMO mode of operation.

CERC directed the task force constituted under Member (Thermal), CEA to complete

the testing / tuning of identified units and finalize the protocols / modalities of testing

in a time bound manner.

9.5.1 POSOCO should take up with Central Commission the

issue of inconsistency between Congestion regulation and

the detailed procedure framed there under so that

congestion due to forced outages and Unscheduled

Interchange (UI) can be handled effectively.

Action: POSOCO

Time Frame: 1 month

CERC vide order issued on 18.12.2012 has directed staff of the CERC to consider the

proposal by NLDC and initiate amendment process in the CERC Regulations 2009.

CERC staff is working on the proposal.

Proposal under active consideration of the Commission and orders expected shortly.

9.5.2

NLDC and each RLDC should have one real-time security

desk in all the shifts to be manned by engineer capable of

carrying out TTC calculations. To facilitate this, manpower

at NLDC and RLDCs need to be enhanced with regulatory

support to take care of financial aspects. Till this

arrangement can be firmed up, various scenarios of outages

could be built, which then can be used by despatcher in real

time. Faster algorithm for calculation of TTC may be

adopted by the load despatchers to update it in real time

under outage conditions.

Action: POSOCO


Updated version of PSS/E is installed at all SLDCs, RLDCs, NLDC, RPCs, CEA and

CERC enabling simulation of the system and carrying out stability studies.

Presently all planned outages are approved and TTC is reviewed and updated, if

required, for these conditions.

9.6 Outage planning of inter-State and inter-regional

transmission elements should be carried out in a

coordinated manner at RPC fora (say Operation Co-

This provision has been implemented. NLDC has been asked to depute its

representatives to attend monthly OCC meetings in all the five RPCs to ensure proper

implementation of this provision.

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ordination sub-committee of RPCs) in accordance with

regulation 5 of Central Electricity Authority (Grid

Standards) Regulation, 2010 and Section 5.7.1 of Indian

Electricity Grid Code. In case need for emergency

maintenance arises in between two meeting of Operation

Co-ordination sub-committee, NLDC and RLDCs should

allow such maintenance after carefully looking at prevailing

system conditions under intimation to RPC Secretariat.

Action: RPCs


9.7 In order to avoid frequent outages/opening of lines under

over voltages and also providing voltage support under

steady state and dynamic conditions, installation of

adequate static and dynamic reactive power compensators

should be planned.

Action: CEA, CTU, STUs


Installation of Fixed Reactors as already approved in various RPCs are under various

stages of implementation. Further study on dynamic support is in progress by CTU

and POSOCO in consultation with CEA.

9.8 The powers of Load Despatch Centres and Regulatory

Commissions related to non-compliance of

statutory/regulatory provisions including that for non-

compliance of directions and non-payment of UI charges,

need review. Appropriate amendments need to be carried

out in the Electricity Act, 2003 after such review.

Action: Ministry of Power, GoI.


Report of the Committee constituted under the chairmanship of Chairperson CEA to

be submitted to MoP on amendments in the Electricity Act 2003 relating to grid

matters shortly.

9.9.1 The regulatory provisions regarding absorption of reactive

power by generating units needs to be implemented

Action: POSOCO


As per system requirement the generators are being advised to absorb reactive power

to control voltage. All RLDCs have issued communication to the Generators in this

regard. The matter is also being discussed regularly in the Operation Co-ordination

Sub-committee meetings of RPCs.

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9.9.2 An audit of devices such as HVDC, TCSC, SVC and PSS

should be done immediately to ensure that their stability

features are enabled. Further, exercise of PSS tuning should

be planned and implemented. Settings of these dynamic

stabilizing devices should be reviewed at appropriate

intervals.

Action: CTU, STUs, Generators


As per information from CTU, audit of Rihand-Dadri HVDC and Pasauli HVDC has

been done and the stability features thereof are enabled. SVC is installed at Kanpur

substation only and it is ON. TCSCs - installed at Gorakhpur, Purnea and Raipur only

and the audit has been done. It was reported by PGCIL that TCSCs are functional.

RPCs will deliberate this as well as implementation of other recommendations by the

utilities in their forthcoming RPC / TCC meetings.

9.9.3 Functioning of existing PMUs and availability of their

output to RLDCs and accuracy of time synchronization

should be monitored on daily basis and, if required,

corrective actions should be taken on priority basis.

Action: CTU, POSOCO


POWERGRID has time synchronized all the existing PMUs that have been installed

under pilot project in identified substations in the country and made them fully

functional. The real time output displays of the PMUs are now being accordingly

made available to the respective system operators in the concerned RLDC. The PMU

data from various locations is also available at the NLDC Control Room.

9.10.1

The synchrophasor based WAMS employing PMUs offer a

wide applications for real time monitoring and control of

the system, specially under the dynamic conditions.

Adequate number of PMUs should be installed to improve

the visibility and real time monitoring of the system.

Further the applications related to the synchrophasor based

wide area monitoring, protection and control should be

embedded in the system.

Action: CTU

Time Frame: 1 year

Unified Real Time Dynamic State Measurement (URTDSM) system with large scale

deployment of PMUs is being discussed with various RPCs prior to taking up with

CERC for approval. Meanwhile, preparation of DPR and tender document by CTU is

in progress. NIT floated in December 2012.

9.10.2

Possibility of voltage collapse prediction, sensing global

power system conditions derived from local measurements

may be explored.

Action: RPCs

It is learnt that voltage collapse prediction relays are available in the market. RPCs

are in the process of examining use of such relays through discussions in the

respective Protection Coordination Sub-committee meetings.

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Time Frame: 1 year

9.11 Need of Dynamic Security Assessment and review of State Estimation In order to assess the system security in

real time and assess the vulnerability condition of the

system, dynamic security assessment need to be

periodically carried out at the control centers. A proper

review and upgradation of the state estimation procedure is

required to improve the visibility and situational awareness

of the system.

Action: POSOCO


As per information from POSOCO, present system does not have dynamic security

assessment capability. New systems are being developed / planned for the future.

9.12 Efforts should be made to design islanding scheme based

on frequency sensing relays so that in case of imminent grid

failure, electrical islands can be formed. These electrical

islands can not only help in maintaining supply to essential

services but would also help in faster restoration of grid.

Action: CEA, RPCs, POWERGRID, STUs, SLDCs and

Generators


NR : NAPS and RAPS islanding schemes are already functional. Islanding scheme

for Delhi has been finalised by DTL in October 2012 and the same is under

implementation. Punjab developed islanding schemes for GGSSTP Ropar with

Gobindgarh area load , GHTP & GNDTP with Bathinda area load and the same is to

be taken for implementation . UP submitted islanding schemes around Unchahar

thermal power stations Haryana submitted its islanding schemes around Faridabad

Panipat power stations .Islanding schemes for UP and Haryana has been deliberated

22-01-2013 in NRPC and they were advised to revise the scheme as per the decisions

in the meeting. UP submitted the revised and final islanding scheme. Rajasthan

initiated preparation of islanding schemes.

WR : Mumbai, Ahmedabad, GTPS Uran islanding schemes are already functional.

Islanding schemes for Vadodara, Bhopal and Nagpur are under study. All CPPs are

planned for islanding at a slightly higher frequency than 48.8 Hz so that these

stations are available for extending startup power.

ER : CESC and many CPPs like Bokaro Steel, NALCO, etc. already have islanding

schemes. Three islanding schemes viz. Bakreshwar with WB load, Chandrapura of

DVC and Bandel TPS, are finalized and the process for implementation of these

schemes have been initiated.

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SR : Islanding schemes for Hyderabad and Chennai are already functional. 14

islanding schemes in the states of AP, Karnataka, Tamilnadu, Kerala around power

stations located in these states have been taken up for study by the respective STUs.

NER : An islanding scheme around Namrup TPS in Assam is already functional.

Eight new islanding schemes have been taken up for study / examination.

9.13.1

As National Grid is on the horizon, homogenization of

system operation philosophy is need of the hour. The

present organizational set up of Load Despatch Centres

need to be reviewed. System operation needs to be

entrusted to Independent System Operator (ISO). In

addition, SLDCs should be reinforced and ring fenced for

ensuring functional autonomy.

Action: Govt. of India, State Govts.

Time Frame: 1 year

Although POSOCO in 100% subsidiary company of PGCIL, it has functional and

financial autonomy in grid operations. Further, strengthening of SLDCs is required to

be done by the states.

9.13.2

Training and certification of system operators need to be

given focused attention. Sufficient financial incentives need

to be given to certified system operators so that system

operation gets recognized as specialized activity.

Action: Govt. of India, State Govts.


Discussed on 21st August 2012 in the proposed National Power Committee meeting

with participation of Chairmen of RPCs/TCCs and the Member Secretaries for

implementation in the respective regions.

Maharashtra has already started such scheme. Other State Govts. have to start the

incentive scheme in this regard.

9.14

Intra-State transmission system needs to be planned and

strengthened in a better way to avoid problems of frequent

congestion.

Action: STUs

Time Frame: 2 years

SLDCs should provide inputs to the respective STUs for better planning /

strengthening of intra-state transmission system. This needs to be implemented and

monitored through RPCs.

In NR, STUs have already been requested through OCC meeting to plan and

strengthen their Intra-state transmission network. This would be continuously

monitored at NRPC forum.

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9.15.1

Appropriate amendments should be carried out in Grid

Connectivity Standards to restrain connectivity of a

generating station or a transmission element without

required communication and telemetry facilities.

Action: CEA.


Connectivity standards are already having the requisite provisions in regard to the

communication and telemetry facilities and as such amendment is not needed.

9.15.2

The Communication network should be strengthened by

putting fibre optic communication system. Further, the

Communication network should be maintained properly to

ensure reliability of data at Load Despatch Cenres.

Action: CTU and STUs

Time Frame: One years

PGCIL have informed that requirement of Fibre Optic link for effective

communication is being worked out by them with STUs through different RPCs and

its implementation is being done in a progressive manner. The work of laying Fibre

Optic cables in all the regions is being awarded progressively from December 2012

and is likely to be completed by the year 2014. Some of the states like J&K, Punjab

have also sought assistance from PGCIL in installing fibre optic communication

network.

9.15.3

RTUs and communication equipment should have

uninterrupted power supply with proper battery backup so

that in case of total power failure, supervisory control and

data acquisition channels do not fail.

Action: CTU and STUs


PGCIL have intimated that at all locations batteries have been replaced except 6

locations in NR and rest of the other region it has been replaced.

9.15.4

In case of existing generating stations or transmission

elements without telemetry facility, the same should be put

in place at the earliest. If prolonged operation without

telemetry continues, POSOCO should approach Central

Commission.

Action: RPCs, POSOCO


The status of availability of Telemetry from various stations is being monitored

closely by the RLDCs/NLDC. In case of non-availability of data from any location,

the matter is being taken up with the concerned agency.

NRPC and ERPC have also taken up the matter with the ISTS users at OCC / RPC

forum and are monitoring the same.

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9.16

Large variations are observed in time taken for initiation of

unit start up (Boiler light up) by the stations after

availability of start-up power and also for start ups/light up

of subsequent units. While subsequent start-ups were very

fast (10-20 minutes) in some of the units, in other cases

they took considerably longer time – several hours. Reasons

for the delays in attempting first start-up and subsequent

start-ups may be examined by the utilities in consultation

with CEA. A standard procedure for preparatory activities

and sequence of start up may be put in place by the stations

to restore units as early as possible particularly in

contingencies.

Action: CEA, Generating Utilities and RLDCs

Time Frame: one year

Meeting was taken by Member (GO&D), CEA on 28th

Aug., 2012 with POSOCO,

NTPC & NRPC to examine delay in extension of start-up power to thermal power

stations, wherein suggestions have been made to accelerate the process. Minutes have

been sent to RPCs & CERC for discussion / implementation / suitable action on the

suggestions and feedback to CEA. Gist of the suggestions enclosed at Appendix-II.

Action plan prepared by CEA in this regard has already been circulated to all

Generators in NR and generators have been requested to work on the action plan and

implement the same.

Member (Thermal), CEA is also studying the matter and likely to come up with the

recommendations thereon soon.

9.17 At inter-State level, the entire landscape has changed over

past few years. With de-licensing of generation and

provision of open access in Electricity Act, 2003 and

development of organized electricity markets, lot of

generation is coming in the form of merchant generation.

Four out of the five regions have been integrated and

formation of National Grid is on the horizon. Under such

scenario, there is need to review the Transmission Planning

criteria.

Action: CEA


The review of transmission planning criteria has been completed by CEA. The

revised transmission planning criteria has been circulated to all concerned.

9.18 There is need to reinforce system study groups in power

sector organisations to analyse the system behaviour under

different network status/ tripping of lines/outage of

generators. Where these do not exist, these should be

created.

Action: CEA, CTU and STU

Time Span: one year

CTU is procuring system study software for distributing to various utilities. First

phase of training programme on system studies has been held in September 2012,

where software was distributed to STUs of Northern Region. Similar activity has

been completed in SR in October 2012 and will be repeated in other regions also by

the CTU.

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9.19

It was felt that a separate task force may be formed,

involving experts from academics, power utilities and

system operators, to carry out a detailed analysis of the

present grid conditions and anticipated scenarios which

might lead to any such disturbances in future. The

committee may identify medium and long term corrective

measures as well as technological solutions to improve the

health of the grid.

Action: MOP, CEA

Time Frame: 1 month

The Task Force has been constituted by MoP on 13-12-2012. The Task Force held

meeting five meetings since then. The fifth meeting was held on 8th

March 2013. The

Task Force has initiated the study on present grid conditions and anticipated

scenarios. Relay coordination and general philosophy on islanding scheme is also

under study.

9.20 For smooth operation of grid systems, it is absolutely

important that all the power generating and distributing

stations are connected on a very reliable telecom network.

(i) A proper network may be built up preferably using

MPLS (Multi Protocol Label Switching) which is simple,

cost effective and reliable. In remote place where

connectivity is a problem, the stations can use dedicated

fibre cable from the nearest node.

(ii) Since POWERGRID has its own fibre optic cables,

practically covering all major nodes and power stations, a

proper communication/IT network may be built using

dedicated fibres to avoid any cyber attack on the power

system.

Action: CTU, STUs

Time frame: 1 Yr

CTU have informed that they already have a dedicated independent communication

network in place. Further, they are in the process of developing a Grid Security

Expert System (GSES) at an estimated cost of about Rs.1300 Crore which involves

laying of optical fiber network costing about Rs.1100 Crore for reliable

communication and control of under-frequency & df/dt relay based load shedding,

etc. System will include substations of 132 kV level and above.

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Appendix-I Abstract of protection audit in NR

Basic Protection Audit for all 132 nos. of important sub-stations/switchyard was carried out by POWERGRID in association with CPRI in six phases. The audit had indicated following deficiencies of critical nature:

(i) Replacement of distance relays of static type with Numerical type

(ii) Non-availability/ non-functioning of bus bar protection

(iii) Non-availability/non-functioning of Single Phase Auto Recloser Scheme

(iv) Non-availability/ non-functioning of Disturbance Recorder (DR) and Event Loggers (EL)

(v) Non-availability/ non-functioning of Local Breaker Back up protection

(vi) Earth fault in DC system

(vii) Time synchronization of Disturbance Recorder (DR) and Event Logger (EL)

(viii) Problems relating to DG set

(ix) Problems relating to PLCC/protection coupler

The issue of rectifying the above deficiencies was discussed in the 19th Protection Sub-Committee meeting held on 21.11.2012 and thereafter in the 24th TCC/27th NRPC meetings held on 29th /30th November 2012. During the discussions, it emerged that while some of the deficiencies can be rectified in a short period of about 03 months, the deficiencies which require procurement of new equipment may take about a year. The utilities were advised to submit action plan/action taken to rectify deficiencies observed. So far, only Rajasthan, NHPC, HVPNL, THDC and Karcham Wangtoo Hydro Power Station have submitted the action taken on the deficiencies observed.

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Appendix-II

Suggestions made at the meeting taken by CEA to examine delay in extension of start-up power

CEA had taken a meeting on 28.08.2012 wherein representative from POSOCO, NTPC and NRPC Secretariat were present. In this meeting, it was decided that following actions would help in accelerating the process restoration of the grid and should be discussed in RPC forum for the purpose of monitoring & implementation and feedback forwarded to CEA :

1. All generating stations with self-start facility should be advised clearly to start their unit(s) on house load without waiting for any code / instruction from any agency / authority. However, such generating stations should charge a transmission line, only after receiving a go-ahead signal from the concerned Area LDC / SLDC / RLDC / neighboring substation / generating station for extending the supply further.

2. Various groups need to be formed & trained in each power station / substation to carry out specific tasks so that they may carry out those tasks efficiently during an emergency like a grid-failure.

3. Communication systems needed to be improved between RLDC and SLDCs, SLDCs and Area LDCs, and Area LDCs and substations in the area. This would improve coordination among them and help in connecting proper load during restoration process of the grid.

4. Fixation of charges by CERC for the start-up power extended by a power station to any other power station / utility would eliminate the commercial constraint in quick extension of start-up power. No power station should refuse extension of start-up power during emergencies for any reason except due to a valid technical constraint. The matter may be referred to CERC.

5. POSOCO should evolve a procedure to send communication regarding any grid disturbance to all the power utilities of the country immediately. This might involve the use of SMS on mobiles of heads of different agencies along with posting of preliminary report about the incident on the website of POSOCO for those who want to know the details. This report should be updated periodically, say on hourly basis, after the disturbance. This would help healthy parts of the grid take preventive action and avoid spread of disturbance to those areas. This is also likely to facilitate quick restoration of the grid by getting quick start-up supply from healthy areas.

6. Mock exercise should be carried out regularly by the power stations / substations, particularly those which generally play a prominent role in restoration of the grid. To ensure that the mock exercise was actually carried out by the power station in a realistic manner, the power station concerned should be required to submit a certificate to this effect from an independent 3rd party.

7. POSOCO would send the list of all those central / state transmission lines, which are used for extending the start-up power from a power station / substation to another, to CEA to monitor their healthiness. This list with CEA would be kept updated by POSOCO after each review of the restoration procedure.

Documents

Status Grid Disturbance Report