FREE GOVERNOR MODE OF OPERATION EXPERIENCE IN THE SOUTHERN REGION

FREE GOVERNOR MODE OF OPERATION:- WHY IS IT REQUIRED? SELF – HEALING MECHANISM MOTHER OF ALL CONTROLS A PRIMARY DEFENCE MECHANISM AGAINST GRID OCCURRENCE PREVENTS SECONDARY COLLAPSE DURING RESTORATION MOST EQUITABLE PUBLIC SERVICE OF SECURITY TECHNICAL SOLIDARITY FAST RESPONSE – IMPOSSIBLE TO ACHIEVE WITH HUMAN INTERVENTION ADOPTED AS A STANDARD PRACTICE WORLDWIDE STEADY FREQUENCY NECESSARY FOR PRICE SIGNAL GOVERNORS ARE SYNONYMOUS WITH GRID SECURITY AND INTEGRITY

FREE GOVERNOR MODE OF OPERATION:- WHY IS IT REQUIRED? DEVELOPING GRID FOCUS NOW ON ECONOMY , OPTIMISATION GRID OPERATOR NEEDS TO BE UNSHACKLED FROM THE UNCERTAINITY OF GRID SECURITY IS FGM ACTIVE? WILL UFR’S ACT? UFR IN SOUTHERN REGION THE UNCERTAINITY OF RESPONSE FROM GENERATORS SHOULD BE A THING OF THE PAST

FREE GOVERNOR MODE OF OPERATION:- WHY IS IT REQUIRED? POST ABT SCENARIO: GRID IS THE MARKET PLACE AND FREQUENCY IS THE PRICE SIGNAL CAN WE ALLOW THE PRICE TO FLUCTUATE ALARMINGLY? WILDLY FLUCTUATING PRICE SIGNAL MEANS THE OPTIMISATION VECTOR IS CLOUDED IN ANY OTHER MARKET, SUCH FLUCTUATIONS IN PRICE WOULD HAVE SET OFF ALARM BELLS!!!

FREE GOVERNOR MODE OF OPERATION:- THE PRE-REQUISITES ‘CRITICAL MASS’ VITAL TO THE SUCCESS OF IMPLEMENTATION DECREASED RESPONSE, BLOCKED GOVERNORS – INCREASED STRAIN ON ‘SINCERE’ UNITS JERKY ACTIONS – SHARP FREQUENCY FLUCTUATION STEP CHANGES ARE FORBIDDEN IN THE GRID MITIGATED TO A LARGE EXTENT BY PROPER LOAD MANAGEMENT

FGMO STIPULATIONS IN IEGC 400 MU CONS IN A DAY-1.5% IS 6 MU, 2190 MU IN A YEAR, 2/UNIT IS 4400 MILLION RUPEES IS 440 CRORE RUPEES

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%.”

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.”

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.

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.”

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 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. All thermal and reservoir based hydro generating units of installed capacity 10 MW and above in North Eastern Region.

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)

FREE GOVERNOR OPERATION THE BASICS 400 MU CONS IN A DAY-1.5% IS 6 MU, 2190 MU IN A YEAR, 2/UNIT IS 4400 MILLION RUPEES IS 440 CRORE RUPEES

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.

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

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.

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.

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%

FREQUENCY VS LOAD CURVE Load in % 100% Droop = 5% 50% Frequency in Hz 0% 50 Hz 51.25 Hz 52.5 Hz

400 300 200 160 120 100 80 40

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

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

EFFORTS BY SRLDC ISSUE TAKEN UP AT OCC AND TCC/SREB MEETINGS LETTERS TO CONSTITUENTS VISITS TO LDC’S AND POWER STATIONS TO PROMOTE AWARENESS CO-ORDINATED WITH THE CONSTITUENTS FOR STAGGERING OF LOAD CHANGE OVERS TO PREVENT LARGE FREQUENCY FLUCTUATIONS KADAMPARAI PUMP OPERATION INTER REGIONAL EXCHANGE TYPICALLY ABOUT 50 SET POINT CHANGES IN A DAY SYNCHRONOUS CONDENSER OPERATION COMMERCIAL HURDLES OBVIATED CERC ORDER ALLOWING 101% AND 105%

SUGGESTED REGULATORY REQUIREMENT ONUS OF PROVING THAT THE UNIT IS ON FGMO TO LIE WITH THE GENERATOR EVERY POWER PLANT IN-CHARGE (UNDER FACTORIES ACT ) TO SELF CERTIFY FGMO ON QUARTERLY BASIS EVERY SLDC TO CERTIFY FOR ITS CONTROL AREA RLDC TO FILE COMPLIANCE IN ITS QUARTERLY REPORT AS PER IEGC

CAPACITY ON FGMO IN SR ( HYDRO < 50 MW & THERMAL < 200 MW ) STATE CAPACITY ON FGMO ( MW ) HYDRO THERMAL/ GAS TOTAL ANDHRA PRADESH 760 KARNATAKA 120 KERALA 433 TAMIL NADU 780 390 1,170 ISGS 1,333 1,150 2,483 DETAILS

AUTOMATIC UFR RELAYS SET AT 48/47.8/47.7/47.6 HZ UPTO FEB 2003 FREQUENT OPERATION: FREQ < 47.8 : 11728 TIMES MOSTLY DISCONNECTED SETTING RAISED TO 48.2/48.0/47.8 HZ IN MARCH ’03 OPERATED ONCE ON 10TH JUNE ‘03 CONSTITUENTS GAINED CONFIDENCE SETTINGS RAISED TO 48.5 /48.2/48.0 HZ IN AUG ’03 ACTED ONLY ONCE TILL NOW:- 5TH MARCH ‘04

KADAMPARAI OPERATION: PRE FGMO AROUND 600 MU PUMPED SINCE JAN 2003 TRIPPING DUE TO SUDDEN FREQ RISE NEXT: KADAMPARAI OPERATION - POST FGMO

03-SEP-2003 NEXT

23-MAY-2004

FREE GOVERNOR MODE OF OPERATION PRACTICAL EXPERIENCES

ANALYSIS OF FREE GOVERNOR MODE OF OPERATION TRIPPING OF TALCHER-KOLAR AT 17:47HRS ON 26-JAN-05

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 ISGS NTPC - 1 NO RESPONSE FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ NTPC 1 TO 3 NO RESPONSE

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 ISGS NTPC - 4 FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 ISGS NTPC - 5 NO RESPONSE FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ NTPC 6 NO RESPONSE

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 ISGS NLY II - 1 NO RESPONSE FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ NLY II 2 TO 7 NO RESPONSE

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 ISGS NLY TPS 1 (Exp) 2 NO RESPONSE FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 ISGS KAYAMKULAM 1 KAYAMKULAM OTHER UNITS SAME RESPONSE FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 APGENCO VTS 2 FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 KSEB IDDUKKI 2 FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ IDDUKKI OTHER UNITS SAME RESPONSE

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 TNEB TTPS 1 FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ

FREE GOVERNOR MODE OF OPERATION ON 26-JAN-05 TNEB MTPS 2 FREQ RISE FROM 49.91 HZ TO 49.50 HZ i.e. ~ 0.41HZ

ANALYSIS OF FREE GOVERNOR MODE OF OPERATION LOAD CHANGE OVER AT 18:00HRS ON 05-FEB-05

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NTPC - 1 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NTPC - 2 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NTPC - 3 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NTPC - 4 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NTPC - 5 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NTPC - 6 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY II 1 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY II 2 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY II 3 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY II 4 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY II 5 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY II 6 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY II 7 Out FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY TPS 1 (Exp) 1 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 ISGS NLY TPS 1 (Exp) 2 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 APGENCO RYTPS 1 RYTPS 2 SAME RESPONSE FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 KPCL SHARAVATHI 1 SHARAVATHI UNITS WERE EITHER NOT AVAILABLE OR VERY LESS GENERATION @ 18:00HRS FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 KPCL VARAHI 1 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ VARAHI 2 SAME RESPONSE

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 KSEB IDDUKKI 1 IDDUKKI UNITS WERE EITHER NOT AVAILABLE OR VERY LESS GENERATION @ 18:00HRS FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 KSEB SABRIGIRI 1 SABRIGIRI OTHER UNITS SAME RESPONSE FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 TNEB NMTPS 1 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ

FREE GOVERNOR MODE OF OPERATION ON 05-FEB-05 TNEB ETS 5 FREQ RISE FROM 49.80 HZ TO 50.74 HZ i.e. ~ 0.94HZ