1 PRESENTATION ON FREQUENCY CONTROL AND FREE GOVERNOR OPERATION TO THE OFFICERS OF CENTRAL ELECTRICITY AUTHORITY On 4 th April, 2005 by V.K. Agrawal SRLDC, Bangalore

2 PRESENTATION OVERVIEW  REGIONAL GRIDS – QUICK FACTS  GRID OPERATION – TYPICAL ISSUES IN THE PAST  GRID PRESENT STATUS – CARDINAL EVENTS  FGMO – STIPULATIONS IN IEGC  FREE GOVERNOR OPERATION – THE BASICS  FGMO – CASE STUDIES IN DIFFERENT REGIONS  ISSUES OF FURTHER INTEREST – ACTION PLAN

3 REGIONAL GRIDS QUICK FACTS

4 SOUTHERN REGION WESTERN REGION EASTERN REGION NORTHERN REGION NORTH- EASTERN REGION INSTALLED CAPACITY NORTHERN :- 31,230 MW EASTERN :- 17,697 MW SOUTHERN :- 31,931 MW WESTERN :- 32,354 MW NORTH-EASTERN :- 2,357 MW TOTAL 115,569 MW REGIONAL GRIDS

5 SOUTHERN REGION WESTERNRE GION EASTERN REGION NORTHERN REGION NORTH- EASTERN REGION ‘ ELECTRICAL’ REGIONS SAME FREQUENCY FROM GUJARAT TO ARUNACHAL PRADESH WITH EFFECT FROM MARCH 2003 ABOUT 2800 KMS! APART

6 SOUTHERN REGION WESTERNRE GION EASTERN REGION NORTHERN REGION NORTH- EASTERN REGION ‘ELECTRICAL’ REGIONS 1 2 WITH THE COMMISSIONING OF THE TALA PROJECT CONNECTING THE EASTERN AND NORTHERN GRIDS, INDIA WILL HAVE ONLY TWO GRIDS

7 Growth of installed capacity for electricity in India

8 Power development - 16th EPS projections : Peak requirement in MW Energy requirement in BU

9 Sourcewise composition of installed capacity in India ( 1,15,569 in 2004)

10 TYPICAL LOAD CURVE OF SR WINTER MONSOON SUMMER EVENING PEAK WEATHER RESERVOIRCONSUMPTIONSECTOR-WISE HYDRO THERMAL

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14 GRID OPERATION TYPICAL ISSUES IN THE PAST

15 GRID OPERATION – TYPICAL ISSUES IN PAST LOW / HIGH FREQUENCY PROBLEMS –FREQUENCY EXCURSES TO LOW/HIGH VALUES LOW / HIGH VOLTAGE OPERATION –CRITICALLY LOW VOLTAGES AT LOAD CENTRES –SUBSTANTIALLY HIGH VOLTAGES AT FAR ENDS SYSTEM BROWNOUTS / BLACK OUTS –SEPERATION OF SYSTEMS / LOSS OF LOAD ECONOMIC IN-STABILITY / INCREASED ELECTRICAL LOSSES –UNRELIABLE / INEFFICIENT OPERATION OF EQUIPMENT

16 GRID PRESENT STATUS

17 GRID OPERATION – PRESENT STATUS  STABILISED SYSTEM FREQUENCY STABILISED SYSTEM FREQUENCY  IMPROVED VOLTAGES IMPROVED VOLTAGES  MERIT ORDER OPERATION MERIT ORDER OPERATION  OPERATIONAL EXCELLENCE OPERATIONAL EXCELLENCE  INTER REGIONAL EXCHANGES INTER REGIONAL EXCHANGES  IMPROVED GRID SECURITY IMPROVED GRID SECURITY JAN - 02JAN - 03 Vol

18 GRID PRESENT STATUS CARDINAL EVENTS

19 GRID PRESENT STATUS -- CARDINAL EVENTS AVAILABILITY BASED TARIFF UNIFIED LOAD DESPATCH SCHEME GENERATION ADDITION INTERREGIONAL AC / HVDC LINKSINTERREGIONAL AC / HVDC LINKS REFORMS IN POWER SECTOR SCHD DRWL

20 FGMO STIPULATIONS IN IEGC

21 EXTRACTS FROM INDIAN ELECTRICITY GRID CODE Section 6.2(e) “ All generating units which are synchronized with the grid, irrespective of their ownership, type and size, shall have their governors in normal operation at all times. If any generating unit of over fifty (50) MW size (10 MW for North Eastern region) is required to be operated without its governor in normal operation, the RLDC shall be immediately advised about the reason and duration of such operation. All governors shall have a droop of between 3% and 6%.”

22 EXTRACTS FROM INDIAN ELECTRICITY GRID CODE Section 6.2(f) “Facilities available with/in load limiters, Automatic Turbine Run up System (ATRS), Turbine Supervisory control, coordinated control system, etc. shall not be used to suppress the normal governor action in any manner. No dead bands and/or time delays shall be deliberately introduced.”

23 EXTRACTS FROM INDIAN ELECTRICITY GRID CODE Section 6.2(g) “All generating units, operating at/up to 100% of their Maximum Continuous Rating (MCR) shall normally be capable of (and shall not in any way be prevented from) instantaneously picking up five percent (5%) extra load for at least five (5) minutes or within technical limits prescribed by the manufacturer when frequency falls due to a system contingency. The generating units operating at above 100% of their MCR shall be capable of (and shall not be prevented from) going at least up to 105% of their MCR when frequency falls suddenly.” “Any generating unit of over fifty (50) MW size (10MW for NER) not complying with the above requirement, shall be kept in operation (synchronized with the grid) only after obtaining the permission of RLDC.

24 EXTRACTS FROM INDIAN ELECTRICITY GRID CODE Section 6.2(h) “The recommended rate for changing the governor setting, i.e. supplementary control for increasing or decreasing the output (generation level) for all generating units, irrespective of their type and size, would be one(1.0) percent per minute or as per manufacturer’s limits. However if the frequency falls below 49.5 Hz, all partly loaded generating units shall pick up additional load at a faster rate according to their capability.”

25 EXTRACTS FROM INDIAN ELECTRICITY GRID CODE Section 1.6 The dates from which the stipulations under sections 4.8(c), 4.8(d), 6.2(e), 6.2(f), 6.2(g) and 6.2(h) would come into effect shall be the date for implementation of the Commercial mechanism for (i)All generating units of installed capacity 200 MW and above and reservoir based hydro units of installed capacity 50 MW and above in SR, ER, NR & WR. (ii)All thermal and reservoir based hydro generating units of installed capacity 10 MW and above in North Eastern Region.

26 EXTRACTS FROM INDIAN ELECTRICITY GRID CODE Section 1.6 (contd.) For all other generating units the date of implementation of stipulations under section 4.8(c), 4.8(d), 6.2(e), 6.2(f), 6.2(g) and 6.2(h) would be three months after the date of implementation of the Commercial mechanism (ABT)

27 FREE GOVERNOR OPERATION THE BASICS

28 VARIATION IN FREQUENCY  Sudden addition of load causes a drop in frequency.  An increased load is supplied through an increase in the load angle by which the rotor lags the stator field.  It means a loss of Kinetic Energy of the rotating M/c and a slower speed of rotation i.e. a lower frequency. f = (P/2) X (N/60) Where f = frequency of the system P = no of poles of the M/c. N = rpm of the M/c.

29 PRIMARY CONTROLS TO REGULATE FREQUENCY  Relief by frequency dependent load  Free Governor Operation  Under Frequency Operation

30 GOVERNOR  Speed governor is the controlling mechanism which controls the input to the prime mover automatically when there is a change in system speed (frequency)  When there is a change in speed (frequency), governor responses by causing valves/gates to open/close to increase/decrease the input to the prime mover  The notion that Governor attempts to restore frequency to normal is a misconception. In reality, Governors attempts to restore load generation balance, using frequency change as a signal.

31 PRIMARY CONTROL - GOVERNOR ACTION Primary control involves the action of turbine speed governors in generating units, which will respond where the speed (frequency) deviates from the speed (frequency) set point as a result of an imbalance between generation and demand in the synchronously interconnected network as a whole. Technical solidarity between members will involve the simultaneous action of primary control on all generating units involved in system control.

32 DROOP  Droop is the amount of speed (or frequency) change that is necessary to cause the main prime mover control mechanism to move from fully closed to fully open.  Normal range -3 to 5%

33 FREQUENCY VS LOAD CURVE 50 Hz 52.5 Hz Hz 100% 50% 0% Frequency in Hz Load in % Droop = 5%

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36 GOVERNING SYSTEM  Hydraulic system has a droop of 5%  Electro-hydraulic system has a droop adjustable from 2.5 to 8%. It is normally set at 5%  In ehtc, droop characteristics is realised through frequency influence on load controller  Frequency influence also acts in cmc for combustion controls

37 BLOCKED GOVERNOR Blocking of governor is bypassing the governing feedback mechanism to maintain fixed generator output.

38 FREE GOVERNOR MODE OF OPERATION CASE STUDY FOR NORTHERN REGION

39 EXTRACTS FROM MINUTES OF NREB BOARD MEETING HELD AT SHIMLA ON 14 th JUNE 2003 “Northern Regional Electricity Board endorsed the decision of Technical Coordination Committee (TCC) to implement free governor mode of operation (FGMO) from 0000 hrs of 1 st Oct, 2003”

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42 UNIT SIZE & GOVERNING SYSTEM S No CategoryTotal Units Capacity (MW) 1500 MW units equipped with EHG governing system and coordinated controls through CMC/ULC/APC: Singrauli,Rihand,Anpara /250 MW units equipped with EHG governing system & coordinated controls through CMC: Kota, Dadri(Th), Unchhar-II, Lehra,Suratgarh MW units equipped with EHG governing system and having manual controls (Without CMC): Unchahar-I, Ropar, Panipat, Anpara-A /210 MW units quipped with hydro mechanical governing system and having manual controls (Singrauli, Obra-B, Badarpur) Total

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47 Above 50.5 HzBelow 49.0 Hz Period% time in IEGC frequency band ( Hz) No. of Excursions % of time No. of Excursions % of time 7 th Oct-30 Oct (Post FGMO) % % 1 st Sept – 6 th Oct (Pre-FGMO) % % COMPARISON OF FREQUENCY PROFILE FGMO

48 FREE GOVERNOR MODE OF OPERATION CASE STUDY FOR SOUTHERN REGION

49 EXTRACTS FROM MINUTES OF 132 nd SREB BOARD MEETING HELD ON ON 5th JULY 2003 The free governor mode of operation (FGMO) shall be implemented in SR from 0000 hrs of 1 st Aug. 2003

50 DETAILS OF GENERATING UNITS IDENTIFIED FOR FGMO IN SOUTHERN REGION THERMAL STATIONS S. NoPower StationAgencyCapacity Installed Capacity (MW) 1 KOTHAGUDAM APGENCO2 * SIMHADRI NTPC2 * VIJAYAWADA APGENCO6 * RAYALASEEMA APGENCO2 * LANCO AP IPP2 * * BSES AP IPP1 * * RAICHUR TPS KPCL7 * NORTH CHENNAI TNEB 3 * TUTUCORIN TNEB 5 * METTUR TNEB 4 * ST - CMS TN IPP1 * NEYVELI II NLC 7 * NEYVELI TPS I (Exp) NLC 2 * RAMAGUNDAM NTPC 3 * * TOTAL 11985

51 HYDRO STATIONS S. NoPower StationAgencyCapacity Installed Capacity (MW) 1 SRISAILAM RB APGENCO7 * SRISAILAM LB APGENCO6 * UPPER SILERU APGENCO4 * LOWER SILERU APGENCO4 * N'SAGAR APGENCO1 * * SHARAVATHI KPCL10 * NAGJHERI KPCL3 * * VARAHI KPCL2 * SHARAVATHI TAIL RACE KPCL4 * KADRA KPCL3 * SUPA KPCL2 * KUTTIADI EXTN. KSEB 1 * IDDUKKI KSEB 6 * LOWER PERIYAR KSEB 3 * SABARIGIRI KSEB 6 * KADAMPARAI TNEB 4 * KUNDAH PH 3 TNEB 3 * KUNDAH PH 4 TNEB 2 * KODAYAR 1 TNEB 1 * ALIYAR TNEB 1 * METTUR TUNNEL TNEB4 * TOTAL 8099

52 STATUS OF FGMO IN SR (ABSTRACT) STATE CAPACITY ON FGMO ( MW ) HYDRO  50 MW (75 NOS) THERMAL/ GAS  200 MW (50 NOS) TOTAL ANDHRA PRADESH3,1803,7556,935 KARNATAKA2,5091,2603,769 KERALA1, ,010 TAMIL NADU8002,5203,320 ISGS---3,990 TOTAL7,49911,52519,024

53 CAPACITY ON FGMO IN SR ( HYDRO < 50 MW & THERMAL < 200 MW ) STATE CAPACITY ON FGMO ( MW ) HYDRO THERMAL/ GAS TOTAL ANDHRA PRADESH0760 KARNATAKA1200 KERALA4330 TAMIL NADU ,170 ISGS000 TOTAL1,3331,1502,483

54 FREQUENCY PROFILE OF SOUTHERN REGION Between HZ :- 100% 02-AUG JULY-03 Between HZ :- 92.8% Between HZ :- 6.9% 02-AUG-02

55 FREQUENCY COMPARISION OF SOUTHERN REGION 09-SEP JULY-03

56 Above 50.5 HzBelow 49.0 Hz Period% time in IEGC frequency band ( Hz) No. of Excursions % of time No. of Excursions % of time 1 st Jul-31 st Jul 03 (Pre- FGMO) % % 1 st Aug-31 st Aug 03 (Post-FGMO) %20.01 % COMPARISON OF FREQUENCY PROFILE FGMO

57 FREE GOVERNOR MODE OF OPERATION CASE STUDY FOR WESTERN REGION

58 CAPACITY WISE (MW) CLASSIFICATION OF GENERATING UNITS IN WR

59 TYPE WISE CLASSIFICATION OF GENERATING UNITS IN WR

60 Units under FGMO on

61 Fig.2 and 3: Frequency improvement after FGMO

62 Frequency improvement after FGMO Indices Average freq Hz50 Hz Std deviation0.3 Hz0.2 Hz Average of squares of morning deviation Hz Hz Average of deviations from 15-minutes average frequency Hz0.004 Hz

63 FREE GOVERNOR MODE OF OPERATION CASE STUDY FOR EASTERN REGION

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67 REDUCED FREQUENCY BAND WITH IMPLEMENATION OF FGMO FREQUENCY DEVIATION REDUCED FURTHER FROM 22 ND JANUARY,04 FROM 22 ND JANUARY,04 FGMO IMPLEMENTATION

68 ISSUES OF IMPORTANCE ACTION PLAN

69 Limitations and Constraints (AS REPORTED BY GENRATORS)  Poor coal quality (All mills are usually in service – no further margins)  Old units, weak boiler parts (Very often operation at throttle pressure below nominal)  Commercial reasons

70 Limitations and Constraints (AS REPORTED BY GENRATORS)  Fear of thermal stresses due to cyclic variation in pressure and temperature.  Fears of choking of mills (when coal quality is poor).  Fear of safety valves propping up.

71 Other Related Issues  Participation in the scheme by all the generators is essential so that the participating units are not subjected to large variations.  Commercial mechanism to be conducive for participation in the scheme.  In the event of loss of generation it should be made up by reserves and/or requisite load shedding.  In order to take care of secondary control a well planned and judicious methodology should follow.

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73 MONSOONS SOUTH WEST MONSOON NORTH EAST MONSOON

74 GRID OPERATION: A TIGHT ROPE WALK BLACK-OUT VOLTAGE COLLAPSE IN-ECONOMIC OPERATION INSTABILITY POWER SWINGS INCREASED LOSSES

75 STABILISED SYSTEM FREQUENCY TYPICAL FREQUENCY CURVE SCATTER DIAGRAM HISTOGRAM OF FREQUENCY FREQUENCY DURATION CURVE Df/dT CURVE RECORD FVI OF 0.04

76 FREQUENCY PROFILE 2002, 2003 & 2004

< & < & < & Above MaxMinAvgFVISt. Dev

78 Voltage at Bangalore Jan 02 & 03

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80 Singrauli & Rihand Pre ABT(Dec 01-Nov 02)Post ABT(Dec 02-Nov 03) Average MW Declared CapabilityInjection Schedule Unchahar-1 & Pre ABT(Dec 01-Nov 02)Post ABT(Dec 02-Nov 03) Average MW Declared CapabilityInjection Schedule Dadri (T) Pre ABT(Dec 01-Nov 02) Post ABT(Dec 02-Nov 03) Average MW Declared CapabilityInjection schedule Anta, Auraiya & Dadri Pre ABT(Dec 01-Nov 02) Post ABT(Dec 02-Nov 03) Average MW Declared CapabiltyInjection Schedule

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82 ABOUT 7000 MW OF CAPACITY IS BELOW 100 Ps ABOUT14200 MW OF CAPACITY IS BELOW 200 Ps ABOUT MW OF CAPACITY IS BELOW 300 Ps CUM. INS. CAP.

HZ

84 MERIT ORDER : UNITS BOXED UP POWER STATIONSTATE CAPACITY(MW) FUEL VARIABLE COST TATA DIESELKARNATAKA 79 DIESEL308 RAYALSEEMA DGPPKARNATAKA 27 DIESEL360 YELEHANKA DIESELKARNATAKA 128 DIESEL314 THANRBHAVIKARNATAKA 220 NAPTHA325 SUB-TOTAL 454 BRAHAMPURAM DPPKERALA 107 DIESEL275 BSESKERALA 157 NAPTHA308 KASARGODE PCLKERALA 22 NAPTHA298 KAYAMKULAMKERALA 360 NAPTHA322 SUB-TOTAL 646 BASIN BRIDGETAMIL NADU 120 NAPTHA584 P.P.NALLURTAMIL NADU 330 NAPTHA415 SUB-TOTAL 450 TOTAL 1550

85 DEEP VALLEY SHARP PEAK

86 KADAMPARAI PUMP OPERATION GENERATOR MODE PUMP SAVINGS OF RS 40 LAKHS EVERY DAY INVESTMENT OF 1600 CRORES SAVED

87 OPPORTUNISTIC UI TRADE POWER EXPORT TO WR ON UI BASIS DURING LOAD CRASH FREQ

88 OPTIMAL RESERVOIR UTILISATION IDUKKI IN KERALA KERALA SAVED RS 50 CRORES BY EFFICIENT UTILISATION OF THE RESERVOIRS AT IDUKKI! POWERGRIDs 400 KV MADURAI- TRIVANDRUM LINE WILL HELP KERALA SAVE EVEN MORE ENERGY IN THE COMING YEAR PLANT OPERATORS AT IDUKKI THINK OF THE RESERVOIR LEVEL IN RUPEES RATHER THAN IN FEET!!! Rs.

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90 MAJOR AND MINOR DISTURBANCES SINCE 1994 NO DISTURBANCES DESPITE LOSING ENTIRE SUPER GENERATING PLANTS LIKE RAMAGUNDAM,VIJAYAWADA,KOTHAGUDEM, NORTH CHENNAI, SHARAVATHY ETC

91 RTU SUB LDC SLDC ERLDC WRLDCNRLDCSRLDCNERLDC NLDC 32 Nos. 51 Nos Nos. Unified Grid Operation 5 Nos. National Level Regional Level State HQ Level Group / Distt Level Plant / Sub- Station Level

92 Growth of installed capacity for electricity in India

93 Kolar Chintamani Cudappah Hoody Hosur Salem Udumalpet Madras B’lore +/- 500 KV DC line 1370 KM Electrode Station Electrode Station TALCHER 400kv System 220kv system KOLAR TALCHER KOLAR SCHEMATIC

94 Inter Regional Links Present IR Capacity = 9,000 MW 700 MW 1200MW 2000MW 900 MW 30,500 MW 16,000 32,700 MW 30,500 MW MW 1650 MW

MW 1000 MW 6450 MW 4600 MW 1300 MW 3200 MW 30,000 MW OF INTER- REGIONAL POWER BY 2012 EASTERN REGION SOUTHERN REGION WESTERN REGION NORTHERN REGION NORTH- EASTERN REGION INTER-REGIONAL TRANSFER BY END OF 11 th PLAN (2012)

96 RESERVOIR LEVEL - COMPARISON LEVEL IN MTS LEVEL31-Dec-03LEVEL31-Dec-04 JALAPUT LINGANMAKKI SUPA IDUKKI KAKKI NILGIRIS TOTAL ENERGY31-Dec-03ENERGY31-Dec-04 RISE IN MU % RISE Only 6500MUs Reserve till next monsoon (5 Months) 43 MUs/day could be generated as against about 63 MUs/day at present.

97 REALITY BITE: FARMERS IN KARNATAKA ARE HAPPY WITH FEWER HOURS OF QUALITY POWER!!. EFFICIENCY OF PUMPS AT TG HALLI WATER WORKS IMPROVED! COMPARISION OF BANGALORE VOLTAGE-TYPICAL DAY BETTER VOLTAGE PROFILE MEANS LESS ELECTRICAL LOSSES

98 WATER SUPPLY TO BANGALORE LOW VOLTAGE PROBLEMS AROUND BANGALORE HAMPERED WATER SUPPLY EARLIER WITH BETTER VOLTAGE NOW, PUMPING EFFICIENCY HAS IMPROVED 400 KV STATION AT MYSORE BEING COMMISSIONED ON WAR FOOTING TO FURTHER FORTIFY THIS PART OF THE GRID PUMPING LOSSES REDUCED ENORMOUS SAVINGS TO THE STATE MOTOR BURNING AND MAINTENANCE COSTS ALSO CAME DOWN DRASTICALLY

99 FREQUENCY CURVE FOR 9 th SEPTEMBER 2004 FVI = 0.04 Avg Freq = 49.99Hz 10 * ∑ (F – 50) 2 FVI = * 60

100 Sector wise consumption of electricity in India in

101 Hydro Thermal mix in India in 2004

102 THANK YOU