30, 31st July 2012 - The India Blackout


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30, 31st July 2012 - The India Blackout

  1. 1. 30-31st July, 2012 Power Blackout in India A reviewCompiled from the CERC investigation report
  2. 2. Contents1. Overview2. Indian Grid System3. Blackout 30th July 20124. Blackout 31st July 20125. Technical Recommendations (1,2,3 and 4)6. Policy Recommendations (1 & 2)7. Proposed changes8. Need for Smart Grids - Future 2
  3. 3. 1. OverviewJuly 30-31,2012 -Biggest Power Blackout in IndianHistory 3
  4. 4. CERC reportCERC conducted an investigation on the causes• Full report on grid disturbance (CERC Order in Petition No. 167/Suo-Motu/2012 dated 1st Aug2012).• CERC released the report titled “Status of action taken on recommendation 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” 4
  5. 5. 2. India National Grid – Hierarchy Indian Grid - NLDC Southern New Grid Region - RLDC Northern Western Eastern North-Eastern SLDCRegion -RLDC Region - RLDC Region - RLDC Region - RLDC SLDC SLDC SLDC SLDC SLDC - State Load Dispatch Centre 5
  6. 6. Types of Transmission line • Mostly within the state220kV • Long distance (State-State, Region – Region)400kV • Long distance state – Region- Region transmission765kV • Latest technology for long distance power transmission with minimum losses.500 kV - • These are much popular in the off-shore wind farm transmission lines in the UKHVDC HVDC – High Voltage Direct Current These systems use direct current for the bulk transmission of electrical power, in contrast with the more common alternating current systems. For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses. 6
  7. 7. Layout – The NEW GRID 7
  8. 8. What is grid disturbance? A grid is said to be disturbed when : f) there is a power a) there is an under failure in the grid voltage (U/V)e) there is a rapid fall b) there is overor rise in frequency ( voltage (O/V)+dF/dT or -dF/dT ) d) there is over c) there is under frequency (O/F) frequency (U/F) 8
  9. 9. Blackout - Affected Regions (30 & 31st July) 9
  10. 10. 29th July – evening before blackout The 400 kV Bina- Gwalior-Agra- 2 was under planned shutdown since 28thJuly 2012 for up- gradation work to 765kV. At 10:18pm, 400 kV Zerda- 28th July 2012 At 3:15pm, 29th July - 220 Kankroli Emergency outage kV Kota-Badod Tripped due for a period of two hours to to operation of distance take out one Tool & Plant (T protection three phase & P) which got stuck with Zone-1 indications at Badod one polymer insulator. end. 10:18pm 3:15pm At 3:40pm, 220 kV Binmal 9:45pm 3:40pm (PG)- Sirohi - Phase to earth At 9:45pm, 400 kV Bhinmal- fault. The two 220 kV Kankroli Tripped due to outlets to Bhinmal(RVPNL) insulator de-capping. and one to Sanchore were in service from Bhinmal. 10
  11. 11. 3. 30th July – 1st blackout 11
  12. 12. Frequency profile as captured by IIT Bombay 12
  13. 13. Reason for blackout -30th July 2012 Summary 400kV Bina-Gwalior-Agra 2 line was under planned shutdown. This caused stress Once almost all the 400kV on other lines. Failure in load lines tripped overnight management and planning (from WR to NR) and even many 200kV lines tripped, Large amount of now the power from WR unscheduled import of started to flow to NR power by the Northern though ER. This caused region from western and power swings in the ER and eastern region. more lines started tripping and caused a complete blackout. Action was not taken to reduce the Total Transfer Capability (TTC) after shut Sipat stage-1 plant was down of Zerda-Kankroli 400 under trial operation and KV line, . The TTC is shown caused unscheduled as 2000 MW before and injection of power. after the shutdown of 400 KV line. Some gas and thermal plants Lack of observation and where tripped in NR due to coordination! forced outage and shortage of coal. Irregular Maintenance and lack of monitoring 13
  14. 14. After Blackout – 30th July 2:33am 14
  15. 15. Restoration – after blackout 30 th July• The blackout happened exactly at time – 2.33am . This affected 8 states and 1 U.T (Rajasthan, Haryana, New Delhi, J&K, Punjab, U.P, Himachal Pradesh, Uttarakhand and Chandigarh)• Emergency loads like railway station, hospitals, airport were supplied with power by 8am• By 10am 40% of the loads where restored.• 100% load was restored by 4pm evening the same day.Following slides shows how the restoration process was carried out! 15
  16. 16. Self supported Islands – After blackout 16
  17. 17. Restoration – from Eastern Region 17
  18. 18. Restoration – from Western Region 18
  19. 19. 4. 31ST July Blackout• The Black out happened exactly at time – 1.00pm . This affected 21 states and 1 Union Territory. This caused much bigger effect than the 30th July Blackout.• The following states were affected by the grid failure: – States on the northern grid: Delhi, Haryana, Himachal Pradesh, Jammu & Kashmir, Punjab, Rajasthan, Uttar Pradesh, Uttarakhand – States on the eastern grid: Bihar, Jharkhand, Orissa, West Bengal – States on the northeast grid: Arunanchal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim• The worst sufferers were 265 miners who got trapped in coal mines in West Bengal and Jharkhand due to the power outage. They were evacuated after hours of agony. 19
  20. 20. 31st July -2nd blackout 20
  21. 21. Frequency shoot up at western region (WR)In the Western Region due to loss ofexport to rest of the NEW grid, thefrequency shot up to 51.46 Hz andmany generating units andtransmission lines tripped due toprocess related issues and highvoltage respectively.The frequency stabilized at around51.0 Hz. The rise in frequency onlyillustrates the poor level ofprimary response. 21
  22. 22. Reason for blackout 31st July 2012 Summary Loss of 400 kV Bina-Gwalior link: Similar to the initiation of the disturbance on 30th July, 2012, tripping of 400 kV Bina-Gwalior line on zone-3 protection of distance relay, due to load encroachment, caused the NR system to separate from the WR system. The UFR load shedding was not adequate to bring Weak Inter-regional the frequency back to a Corridors due to multiple safer level of 49.5 Hz and outages above. Inadequate Response by SLDCs to RLDCs’ High Loading on 400 kV instructions on this day Bina-Gwalior-Agra link also to reduce overdrawl by -NR utilized Unscheduled the NR utilities and Interchange (UI) and this underdrawal by the WR lead to overloading utilities 22
  23. 23. Restoration after blackout -31st July• Total affected load because of Blackout was 48,000MW• Emergency loads like railway station, hospitals were supplied with power by 3:30pm• 100% load was restored by 9.30pm evening, the same day. 23
  24. 24. Recommendations of the Committee 24
  25. 25. 5. Technical Recommendations -1• Review protection schemes along with Immediate review of zone-3 philosophy• Synchro-phasor measurements from PMUs should be explored for protection systems• A complete independent audit of time synchronization of DRs, ELs and PMUs• Frequency band tightening up close to 50 Hz• Review of UI mechanism• STUs should immediately enable under frequency and df/dt based load shedding schemes• Faster algorithm for calculation of TTC.• The regulatory provisions regarding absorption of reactive power by generating units needs to be implemented 25
  26. 26. Technical Recommendations -2• Installation of adequate static and dynamic reactive power compensators should be planned.• 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.• The Synchro-phasor 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.• Possibility of voltage collapse prediction, sensing global power system conditions derived from local measurements may be explored 26
  27. 27. Technical Recommendations -3• Islands: 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. This will also help in faster restoration of grid.• The Communication network should be strengthened by putting fiber optic communication system. Further, the Communication network should be maintained properly to ensure reliability of data.• UPS - 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.• Telemetry facility at all generating station and transmission liens – at the earliest. 27
  28. 28. Technical Recommendations -4• 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• An audit of devices such as HVDC, TCSC, SVC and to ensure their stability features are enabled.• 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)(ii) IT network may be built using dedicated fibres to avoid any cyber attack on the power system. 28
  29. 29. 6. Policy Recommendations-1• Implementation of various regulations issued under the Electricity Act, 2003 and look into violation SERIOUSLY.• Real-time security desk in all the shifts to be manned by engineer capable of carrying out TTC calculations (in NLDC and RLDC).• LDC and Regulatory Commissions related to non-compliance of regulatory provisions including that for noncompliance of directions and non-payment of UI charges, need review.• The present organizational set up of Load Dispatch Centres need to be reviewed.• Training and certification of system operators need to be given focused attention. 29
  30. 30. Policy Recommendations-2• There is need to reinforce system study groups in power sector organizations to analyze the system behavior under different network status/ tripping of lines/outage of generators. Where these do not exist, these should be created.• Intra-State transmission system needs to be planned and strengthened in a better way to avoid problems of frequent congestion• Special task force - 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.• Sufficient financial incentives need to be given to certified system operators so that system operation gets recognized as specialized activity. 30
  31. 31. 7. Proposed protection study • Phasor Measurement Units (PMU) • These are highly sophisticated instruments to measure change inInstallation voltage/current in milliseconds.of PMUs : 31
  32. 32. Relay Protection • These connected on the transmission lines • Distance relays will sense a fault/disturbance in the grid and give a trip commandDistance to the incomer breaker whenever the grid disturbance exceeds a set limit.Relays: • By opening the incomer breaker, the plant/line is isolated from the grid. • These perform mathematical algorithms and to offer very high accuracy & resolution.Numeric • These help in detection of dF/dT fault (change in frequency) Relays: 32
  33. 33. Study of Zone 3 faulty tripping by DR• Line Fault - Usually any fault in the zone 3 region due to phase-phase fault, phase- ground or other faults will activate the distance relay to open the circuit (Circuit Breaker – VCB/SF6-CB)• Overloading - If there is overloading this will also create a low impedance on the lines and lead to zone 3 fault alert. Before the far distance relays operate, the local relays should sense this and the appropriate load shedding should be done.• Failure - If failure of load shedding, the far distance relay operate and this leads to blackout of the entire distribution lines. (This can be a major reason for 30,31st July blackout, So proper considerations should be made for load characteristics)Please find a example picture in the next slide. 33
  34. 34. Distance Relay Operation 34
  35. 35. Study of UFR /(dF/dT) under load encroachment conditions• What really happened – to the protective UFR and dF/dT relays? Why didn’t they help in load shedding to improve the declining frequency in Northern region (NR and ER during 31st) on 30th blackout.• Similarly in the western region the frequency rose up to 51.4Hz, and none of the generators units responded to this frequency hike.• A separate study has been proposed by the authorities to study regarding the settings of these relays and fix the issues associated. 35
  36. 36. Study on effects of : TCSC and SVC How these compensators affect What is a compensator? the protection distance relay operation?• A compensator is used in transmission • The Distance Relays (DR) use lines/grid/load for voltage stability, impedance measurement to determine reducing net losses, limiting short circuit the presence of faults. currents, damping power oscillations by compensation of real and reactive • The capacitance cancels or compensates power. some of the inductance of the line and therefore the relay (DR) may perceive a fault to be in its first zone when the fault is actually in the second or third zone of protection. TCSC – Thyristor Controlled Series Capacitors SVC – Static VAR Compensator 36
  37. 37. FUTURE? 37
  38. 38. 8. Why Smart Grids?If you can measure it, you can manage it… To improve efficient Distribution To maximize Generation cyber safety To improve communication between various LDS’ To monitor the loads and shed loads when stress increase or frequency decrease rapidly. To avoid unscheduled transfer of power and blackouts 38
  39. 39. Smart Grid for India BESCOM hasbegun work onits Rs 87-crore T&D smart grid Losses project in the >30% City. 39
  40. 40. Features of Smart Grids • Smart Metering • On line monitoring portal – with help of SCADA systems • Home automationLocal Load level • Public charging stations – for electric cars/bikes • Smart Distribution • Load/demand management • Energy Audit T & D level • Smart protection controls • Renewable energy source integration or Distributed Generation Smart GenerationHere are some slides on Smart Grid solution from GE 40
  41. 41. Smart Metering source: GE 41
  42. 42. Smart Substation source: GE 42
  43. 43. Smart Solutions source: GE 43
  44. 44. Smart Communication source: GE 44
  45. 45. Distributed Power Generation• Distributed Generation is nothing but Generation at site.• The most popular source for distributed generation is solar PV• Germany has the largest percentage mix of solar PV DG at LV level in their total energy mix. Germany has also developed their own grid codes for LV generation and grid connection (recent policy– reactive power control, using solar grid inverter).Source: BELELECTRIC 45
  46. 46. Distribution level voltage issues (LV)• The voltage level at the end consumer side face voltage drop due to transmission losses, line impedance (R+JXL) and increase in load. source: GE 46
  47. 47. Pros and Cons of Distributed Generation• Here the voltage level gets stabilized due to the feed in power from solar. This can greatly reduce the stress and disturbance on transmission lines.• This can also increase the voltage above a certain level when more solar generators are present and the inverters are forced to trip (overvoltage). This is dangerous and can cause blackouts.• In 2011, Germany came up with some modifications in their grid codes with reactive power controlled solar inverters.• Distributed Generation can reduce the overall T&D losses (from HV, MV, to distribution LV). source: GE 47
  48. 48. LV level frequency and voltage control• Recently grid tie solar inverters come with intelligent active and reactive power control to keep the LV grid voltage and frequency under control.• As shown in the graph below , when the frequency exceed a certain limit - the active power control comes into play and reduces the overall power output to stabilize the local grid.• Similarly when there is a voltage increase, the reactive power is absorbed by the GT solar inverters and this stabilizes the output accordingly (check image down). 48
  49. 49. Summary• In this presentation we had a look at the various events, issues and recovery process carried out before and after the 2012,July blackout.• The recommendation from the committee was also discussed.• Study on the various protection relays and fault tripping• Study on effects of capacitor compensators (SVC, TCSC) on protection relays• Required changes for the future – Smart Grids (Smart metering, communication and renewable energy / distribution generation) 49
  50. 50. Thank youGiridaran Srinivasan Project EngineerRESolve Energy Consultants giridaran@re-solve.in 50
  51. 51. Reference and CreditsConcept papers: TCSC FOR PROTECTION OF TRANSMISSION LINE P.S.Chaudhari#i, P. P.Kulkarni#2, R.M.Holmukhe#3, Mrs.P.A.Kulkarni #4 #iScientist, DRDO, Pune, India, #2DRDO, Pune, India #,,3,4 Bharati Vidyapeeth University College of Engineering, Pune, India.Pictures and other data:• PMU - http://www.qualitrolcorp.com/Products/Q_PMU9/18/36_Phasor_measurement_units_%28PMU%29/• www.erlphase.com(http://www.erlphase.com/downloads/data_sheets/L_PRO_4000_line_protection_relay_ds.pdf)• http://phasormeasurements.blogspot.in/• Distributed Generation – BELELECTRIC• Blackout picture: http://www.desismartgrid.com/2012/08/indian-power-grid-blackout-reasons-and-future-requirements/Blackout official data:• Full report on grid disturbance (CERC Order in Petition No. 167/Suo-Motu/2012 dated 1st Aug2012).• Status of action taken on recommendation 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.Smart Grid:• GE - http://www.gedigitalenergy.com/communications.htm• GE - http://www.gedigitalenergy.com/multilin/catalog/Transmission.htm#prl• L&T - http://www.larsentoubro.com/lntcorporate/ebg/html/grid_islanding.htm• SMA• BESCOM - http://www.deccanherald.com/content/288701/bescom-ropes-us-firm-smart.html• Indian Smart Grid Task Force 51