Indian&Blackouts/&July&30&&&31,&2012& … · Outline! • Impactof!the!two!Indian!blackouts! – th30 !July,!2012!at2:35!AMIndian!Standard!Time! (IST)! – st31 !July,!2012!at1!PMIST!

Indian Blackouts-‐ July 30 & 31, 2012 Recommenda;ons and Further Ac;ons

CAMS/RRPA Panel Session Mitigation and Prevention of Cascading Outages:

Methodologies and Practical Applications PES General Meeting, Vancouver, Canada

July 24, 2013 Anish Gaikwad ([email protected])

Project Manager, Electric Power Research Ins;tute Knoxville, TN, USA

Suresh C Srivastava ([email protected]) Professor, Dept. of Electrical Eng.

Indian Ins;tute of Tech. Kanpur, India

Contribu;ng Authors: Vikas Singhvi, EPRI and Sudhir Agarwal, General Reliability

Outline •  Impact of the two Indian blackouts

– 30th July, 2012 at 2:35 AM Indian Standard Time (IST)

– 31st July, 2012 at 1 PM IST

•  A summary of sequence of events for the two blackouts

•  Root cause analysis and recommendaJons for system planning and operaJons

IEEE Boise, Nov 16, 2012

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Impact of the July 30th Blackout •  Occurred at 2:33 AM IST •  Affected more than 300 million people in Northern Region

across 9 states including the capital New Delhi •  RestoraJon Jme :16:00 PM •  Collapse Jme : 02:33 AM •  MW generaJon lost :more than load loss •  MW load lost :36000 MW •  Number of successive events : no exact count but a large no. •  DuraJon (from blackout to recovery): ~ 13:30 hrs •  Approximate cost : No official data available but a huge

figure


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Impact of July 31st Blackout •  Occurred at 1:00 PM IST •  Affected 670 million people in Northern, Eastern, North-‐

Eastern regions across 22 states •  RestoraJon Jme :All regions by 21:00 PM •  Collapse Jme : 13:00 PM •  MW generaJon lost : more than load loss •  MW load lost :48 000 MW •  Number of successive events : no exact count a but large no. •  DuraJon (from blackout to recovery): ~ 5 hrs (NR), 8 hrs (ER)

and 2 hrs (NER) •  Approximate cost : No official data available but a huge

figure IEEE Boise, Nov 16, 2012

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Indian Regional Grid India has been demarcated into 5 interconnecJons

• Northern (NR) • Eastern (ER) • Western (WR) • North Eastern (NER) • Southern (SR)

NR,ER,NER and WR are synchronously interconnected

SR is asynchronously connected to the rest.

All the regions except SR are together referred to as “NEW” regions

Source: http://www.desismartregion.com/2012/08/indian-power-region-blackout-reasons-and-future-requirements/

Regions in black show the interconnecJons affected by the two blackouts

Blackout-‐1: Prior System CondiJons


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Western and Eastern regions were exporJng power to the Northern region before the event:

• ER to NR export was 2585 MW • WR to NR export was 2862 MW • Grid frequency was 49.68 Hz A large number of lines were out of service parJcularly near WR-‐NR interface before the outage. The system was in an insecure condiJon

InstrucJons from NR load dispatch center to shed loads were neglected by states in NR

Blackout-‐1: Sequence of Events

http://www.thehindu.com/news/national/article3718641.ece http://www.nldc.in/Flasher/Flash%20Report_NLDC_region%20Disturbance%20in%20Northern%20Region_30072012_Revision1.pdf

Outaged lines before the event (Red line is a double ckt.)

The 765 circuit ‘2’(being operated at 400 kV) between Gwalior-‐Agra and 400 kV Zerda-‐Kankroli were down before the event.

• Gwalior-‐Agra ckt ‘2’ was on planned outage since 28th July for upgrade to 765 kV. • Zerda-‐Kankroli line was on planned outage since 07/28

Blackout 1 : Sequence of events Northern states over-‐drawing power than what was scheduled (called as Unscheduled Interchange).

•  This is OK and allowed under Indian electric grid code •  Normally done when there is surplus of power available from the gird as it is much cheaper than power from local Independent Power Producers (IPPs)

•  Operators were aware of overdrawing of power by the states but had no authority to take acJons such as automaJc tripping of the loads.

However, this resulted in tripping of Gwalior-‐Agra (ckt 1) 765 kV line which was being operated at 400 kV

• Tripped due to mis-‐opera;on on zone 3 protec;on due to heavy loading of the line

• DFR logs did not indicate any faults on the system prior to the line trip The outage of the Gwalior -‐ Agra ( ckt 1) caused a big power swing in NR-‐ER interface which eventually led to cascading events •  Power flow from WR to NR started to re-‐route through ER which resulted in tripping of other 400 kV circuits in ER

• Machines in NR started to slow down as compared to the rest of the NEW grid which led to further angular separaJon

•  UFLS and df/dt protecJon schemes were not acJvated in NR •  Primary frequency response from governors was disabled

Blackout 1 – Frequency SeparaJon Frequency separaJon between WR and NR aoer the event

• Rise in frequency in WR close to 51 Hz indicates inadequate primary frequency response from generators

Blackout-‐2: Prior System CondiJons

Again, NR was imporJng power from Western and Eastern regions

• ER to NR export was 1825 MW • WR to NR export was 2100 MW

A large number of lines were out of service before the outage. The system was in an insecure condiJon

InstrucJons from NR load dispatch center to shed loads were neglected by states in NR

Blackout 2 – Sequence of Events •  10 min. prior to the blackout, two 220 kV lines connecJng NR-‐WR were

tripped due to overload due to tripping of a 250 MW thermal plant

•  At 13:00 hrs, Bina-‐Gwalior (ckt 1) the line tripped again on zone-‐3 mis-‐opera;on due to overload

•  This led to angular separaJon between ER and WR and isolated WR from ER+NER+NR

•  Not adequate relief from UFLS and df/dt schemes in NR and ER •  •  No primary frequency response from governors in NEW grid

•  Cascade tripping of lines occurred due to overvoltage, power swing, zone-‐3 protecJon. Generators were tripped on under frequency –  This iniJally separated NR and then resulted in collapse of ER and NER

Blackout 2 – Frequency SeparaJon Frequency separaJon between NR and rest of the NEW grid

Recommenda;ons and Ac;ons Taken as on 3rd July 2013 (Source: CEA New Delhi)

CommiZee’s Recommenda;ons Ac;ons Taken Extensive review/ audit of protecJon system ProtecJon audit in all regions completed

Frequency Control through GeneraJon reserves/Ancillary services and review of present UI mechanism

CERC directed for the formulaJon of drao regulaJons for GeneraJon Reserves/ Ancillary Services

Ensure primary response from generators -‐  CERC re i te ra ted the need fo r compliance by generators

-‐  CERC fixed responsibility for non-‐implementaJon of RGMO / FGMO mode of operaJon

-‐  A Task Force consJtuted to develop procedure for tesJng of primary response of generators

Ensure operaJon of defense mechanisms, like UF & df/dt based load shedding

-‐  All STUs are directed to enable UF and df/dt based load shedding immediately

-‐  High level logic for an automated conJngency load shedding protocol circulated by POSOCO

CommiZee’s Recommenda;on Ac;ons Taken Review of Total Transfer Capability (TTC) procedure and congesJon charges

-‐  Real Jme security desk installed in NLDC -‐  In case of planned outages, LDCs/ NLDC

to do system studies using PSS/E for revision of TTC

Coordinated outage planning of transmission elements

NLDC to depute its representaJve to arend monthly OCC meeJngs in all the five RPCs to ensure proper implementaJon of this provision, for inter-‐regional lines.

InstallaJon of adequate staJc and dynamic reacJve power compensators

-‐  Standing Commiree on Transmission Planning approved InstallaJon of fixed Reactors of the concerned Regions

-‐  Further study on dynamic reacJve compensaJon is in progress by CTU and POSOCO in consultaJon with CEA

Review of penal provisions of the Electricity Act, 2003 to ensure berer compliance of instrucJons of LDCs and Central Commission

Under consideraJon of Ministry of Power

CommiZee’s Recommenda;on Ac;ons Taken OpJmal uJlizaJon of available assets such as HVDC, TCSC, SVC controls

-‐  Stability features of Rihand-‐Dadri HVDC and Pasauli HVDC has been enabled

-‐  TCSCs installed at Gorakhpur, Purnea and Raipur are funcJonal.

-‐  PSS tuning for generators is done Employment of Synchrophasor based WAMS for real Jme monitoring, protecJon and control of the system

Unified Real Time Dynamic State Measurement (URTDSM) system with large scale deployment of PMUs is proposed

Dynamic Security Assessment and faster State EsJmaJon tools at Load Dispatch Centers

-‐  Present system does not have dynamic security assessment capability.

-‐  New systems are being developed / planned for the future.

Islanding schemes for faster recovery in case of grid disrupJons

Region wise Islanding scheme – North -‐ under implementaJon West -‐ operaJonal South -‐ To be implemented by Aug, 2013 East -‐ Under feasibility study North East -‐ Under feasibility study

CommiZee’s Recommenda;on Ac;ons Taken More autonomy to all the Load Dispatch Centers in taking and implemenJng decisions relaJng to operaJon and security of the grid

-‐  States to iniJate acJon on strengthening of SLDCs

-‐  IncenJve scheme for System Operators -‐  Training of system operators iniJated

planning and investment to avoid congesJon in intra-‐State transmission system

SLDCs to provide inputs to the respecJve STUs for berer planning / strengthening of intra-‐state transmission system

Proper telemetry and communicaJon to Load Dispatch Centers

-‐  Fiber OpJc link implementaJon with STUs through RPCs for communicaJon

-‐  The status of the availability of Telemetry from various staJons is being monitored closely by the RLDCs/NLDC.

Shortening of startup Jme of generaJng staJons

CEA, POSOCO, NTPC & NRPC examined delay in extension of start-‐up power to thermal power staJons, and suggesJons have been made to accelerate the process. AcJon plan circulated to all Generators in NR for implementaJon.

CommiZee’s Recommenda;on Ac;ons Taken review transmission planning criteria in view of the growing complexity of the system

Review of transmission planning criteria has been implemented by the CEA and has been put on the website.

Strengthening of system study groups -‐  CTU has procured system study sooware for distribuJng to various uJliJes.

-‐  First phase of training program on system studies has been done.

FormaJon of separate task force to carry out a detailed analysis of the present grid to avoid future disturbances

-‐  The Task Force has been consJtuted, It has iniJated the study on present grid condiJons and anJcipated scenarios.

-‐  Relay coordinaJon and general philosophy on islanding scheme is also under study.

Challenges in Improving Long-term Reliability of the Indian Grid

•  Inadequate coordinaJon in planning, operaJon & maintenance

•  Investments in T&D not in same proporJons as in generaJon •  Lack of Grid Discipline and lack of adherence to grid protocols •  Lack of transparency and red tape •  Overlapping governance by a number of ministries,

departments, and states •  DifficulJes in revenue recovery


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Acknowledgement •  We would like to thank the EPRI personnel:

–  Arshad Mansoor, Sr. VP, R&D, EPRI – Mark McGranaghan, VP, Power Delivery & UJlizaJon, EPRI –  Daniel Brooks, Sr. Program Manager, Grid OperaJons and Planning, EPRI

–  Karen Forsten, Director, Grid OperaJons and Planning, EPRI

•  Central Electricity Authority (CEA) New Delhi, Study Task Force Members and Power System OperaJon CorporaJon Ltd. (POSOCO) New Delhi


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Documents

Indian&Blackouts/&July&30&&&31,&2012& … · Outline! • Impactof!the!two!Indian!blackouts! – th30 !July,!2012!at2:35!AMIndian!Standard!Time! (IST)! – st31 !July,!2012!at1!PMIST!