SUBMITTED BY

ARUN MURALEEDHARANROLL NO 12281

ELECTRICAL AND ELECTRONICS ENGINEERING

NATIONAL INSTITUTE OF TECHNOLOGY HAMIRPUR

TRANSMISSION PLANNING CRITERIA

CENTRAL ELECTRICITY AUTHORITY RESPONSIBLE FOR PREPARATION OF TRANSMISSION PLANS.

AND FOR COORDINATING ACTIVITIES OF PLANNING AGENCIES AS PER ELECTRICITY ACT 2003.

CENTRAL TRANSMISSION UTILIY RESPONSIBLE FOR INTER STATE TRANSMISSION SYSTEM.

STATE TRANSMISSION UTILITY RESPONSIBLE FOR INTRA-STS. BOTH ISTS AND INTRA-STS ARE INTERCONNECTED TO FORM THE

NATIONAL GRID. VOLTAGE LEVELS FOR ISTS: 132kV AND INTRA-STS: 66kV CRITERIA TO BE USED FOR SYSTEMS PLANNED AFTER FEB 2013 EXISTING SYSTEMS WILL BE REVIEWED ACCORING TO THIS AND

ACCORDINGLY ADJUSTMENTS TO BE MADE.

SCOPE

a) TRANSMISSION SYSTEM SERVES AS INTERCONNECTION BETWEEN SOURCE AND LOAD. ISTS AND INTRA-STS ARE THE CLASSIFICATION OF INDIAN TRANSMISSION SYSTEMS. FORMER IS TOP LAYER OF NATIONAL GRID, THE LATTER LIES BELOW IT.

b) TRANSMISSION SYSTEM IS AUGMENTED TO CATER TO LONG TERM POWER REQUIREMENTS. E.g INCREASE IN DEMAND ETC.

c) TRANSMISSION CUSTOMERS AND UTILITIES GIVE THEIR TRANSMISSION REQUIREMENT AND PRDUCTION SO AS TO PREVENT LOAD CONGESTION AND OTHER SUCH PROBLEMS. CUSTOMERS SHALL PROVIDE REASON FOR THEIR TRANSMISSION CONSUMPTION.

d) LONG TERM APPLICANTS ARE SUPPOSED TO SUBMIT THEIR REQUIREMENTS TO CTU/STU TO MAKE AVAILABLE THE REQUIRED DEMAND.

e) FOR EVACUATION OF POWER FROM HYDRO PROJECTS TI BE DONE RIVER BASIN WISE CONSIDERING THE IDENTIFIED GENERATION PROJECTS AND POWER POTENTIAL.

f) FOR CONGESTED AREAS (URBAN AREAS) OR WITH DIFFICULT TERRAIN ETC, TRANSMISSION CORRIDOR MAY BE PLANNED FOR LONG TERM OPTIMISATION KEEPING IN MIND RIGHT OF WAY AN COST. CAN BE DONE BYE USING TECHNOLOGY LIKE HVDC,GIS OR USING MULTI CIRCYUIT TOWERS FOR STRINGING CIRCUITS.

PLANNING PHILOSOPHY

h) STU ACTS AS NODAL AGENCY FOR INTRA-STS PLANNING. STU SHALL BE SINGLE CONTACT POINT FOR ISTS.

i) NORMALLY INTRA STATE ENTITIES TO BE SUPPLIED BY INTRA STATE NETWORK EXCEPT IN EXCEPTIONAL CASES, THEN IT IS SUPPLIED BY ISTS. THEN THIS CONNECTION CAN ALSO BE USED BY OTHER INTER STATE ENTITIES.

j) STU COORDINATE WITH URBAN PLANNING AGENCIES, SEZ DEVELOPERS AND KEEP LAND FOR FURTHER DEVELOPMENT FOR LONG TERM REQUIREMENTS.

k) SYSTEM PARAMETERS AND LOADING OF SYSTEM ELEMENTS TO REMAIN WITHIN PRESCRIBED LIMITS.

l) TO ENSURE SECURITY OF GRID, DURING TIMES OF FAILURE, SUITABLE DEFENSE MECHANISMS SHOULD BE ADOPTED. SUCH AS LOAD SHEDDING, GENERATION RESCHEDULING, ISLANDING ETC.

m) CRITICAL LOADS- RAILWAYS, METRO RAILM AIRPORTS, REFINERIES, PLANTS ETC PLAN THEIR CONNECTION WITH GRID WITH 100% REDUNDANCY.

n) PLANNED TRANSMISSION CAPACITY WOULD BE FINITE. THERE WILL BE POSSIBILITY OF CONGESTION IF LOAD IS MORE THAN ANTICIPATED.

o) COMMUNICATION SYSTEM FOR NEW SUBSTATIONS AND GENERATING STATION SHOULD BE PLANNED BY CTU/STU.

h) THERE SHOULD BE STRENGTHENING OF TRANSMISSION NETWORK WHOSE CHOICES SHOULD BE BASED ON COST, RELIABILITY, RIGHT OF WAY, LOSSES ETC

ADDITION OF NEW TRANSMISSION LINE OR SUBSTATIONS APPLICATION OF SERIES CAPACITORS, FACTS DEVICES ETC TO

INCREASE POWER TRANSFER CAPABILITY UPGRADATION OF EXISTING AC TRANSMISSION LINES TO HIGHER

VOLTAGE USING SAME RIGHT OF WAY RE-CONDUCTORING OF EXISTING AC LINES WITH HIGHER AMPACITY

CONDUCTORS USAGE OF MULTI VOLTAGE LEVEL AND MULTI CIRCUIT LINES USE OF NARROW BASE TOWERS AND POLE TYPE TOWERS IN

URBAN/SEMI URBAN AREAS KEEPING IN COST AND RIGHT OF VIEW OPTIMISATION.

USE OF HVDC TRANSMISSION USE OF GIS/HYBRID SWITCHGEAR.

CRITERIA FOR STEADY STATE AND TRANSIENT STATE

BEHAVIOUR

NORMAL OPERATION, ‘N-0’, ALL ELEMENTS ARE AVAILABLE. ALL PARAMETERS SUCH AS VOLTAGES, LOADINGS, FREQUENCY SHOULD REMAIN WITHIN PERMISSIBLE LIMITS.

‘N-1’ DISTURBANCE; MORE PROBABLE DISTURBANCE. AGAIN ALL PARAMETERS SHOULD REMAIN WITHIN PERMISSIBLE LIMITS.

SECOND CONTINGENCY, LESS PROBABLE, ‘N-1-1’, HERE SOME OF THE EQUIPMENTS MAY BE LOADED UPTO EMERGENCY LIMITS. FOR SUCH A CONTINGENCY, METHODS SUCH AS LOAD SHEDDING/RE-SCHEDULING OF GENERATION MAY HAVE TO BE APPLIED EITHER MANUALLY OR THROUGH AUTOMATIC SYSTEM PROTECTION SCHEMES. TO BE APPLIED WITHING 1.5 HRS AFTER DISTURBANCE.

STEADY STATE &TRANSIENT BEHAVIOUR

NORMAL THERMAL AND VOLTAGE RATINGS: EQUIPMENT LIMITS WHICH CAN BE SUSTAINED ON CONTINUOUS BASIS.

EMERGENCY THERMAL AND VOLTAGE RATINGS: EQUIPMENT LIMITS WHICH CAN BE TOLERATED FOR A SHORT TIME.

LOADING LIMIT OF T.L/THERMAL LOADING LIMIT: DETERMINED BY DESIGN PARAMETERS BASED ON AMBIENT TEMPERATURE, MAX PERMISSIBLE CONDUCTOR TEMPERATURE, WIND SPEED, SOLAR RADIATION, ABSORPTION COEFFICIENT, EMISSIVITY COEFFICIENT ETC. SOME QUANTITIES ASSUMED TO BE FIXED DURING PLANNING.

FOR T.L WITH DIFFERENT TYPES OF CONDUCTORS: BASED ON CONDUCTOR TEMPERATURE LIMIT, RIGHT OF WAY OPTIMISATION, LOSSES IN LINE, COST AND RELIABILITY CONSIDERATIONS ETC.

THE LOADING LIMIT FOR AN INTER CONNECTING TRANSFORMER=NAME PLATE READING. DURING PLANNING, MARGNS ARE KEPT.

EMERGENCY THERMAL LIMITS FOR PLANNING= 110% OF THE NORMAL THERMAL LIMITS.

PERMISSIBLE NORMAL AND EMERGENCY LIMITS

STEADY STATE VOLTAGE LIMITS. (MARGINS ARE ALSO CONSIDERED)

TEMPORARY OVER VOLTAGE LIMITS DUE TO SUDDEN LOAD REJECTION

SWITCHING OVER VOLTAGE LIMITS

800kV SYSTEM 1.9PU PEAK PHASE TO NEUTRAL ; (653kV=1P.U)

420kV SYSTEM 2.5PU PEAK PHASE TO NEUTRAL ; (343kV=1PU)

VOLTAGE LIMITS

1. ‘N-0’

SYSTEM TESTED FOR ALL LOAD GENERATION SCENARIOS VIZ ACTIVE POWER, REACTIVE POWER, GENERATION DISPATCHES AND MODELLING.

ALL EQUIPMENTS ON NORMAL THERMAL AND VOLTAGE RATINGS. ANGULAR SEPARATION BETWEEN ADJACENT BUSES ≤3O°.

2. ‘N-1’

2.1 STEADY STATE EQUIPMENTS AT NORMAL THERMAL AND VOLTAGE RATINGS AFTER

N-1 DISTURBANCE W/O LOAD SHEDDING/ RESCHEDULING OF GENERATION

ANGULAR ≤ 3O°.

RELIABILITY CRITERIA

2.2 TRANSIENT STATEPERTURBATIONS CAN CAUSE TRANSIENTS WHICH ARE

OSCILLATORY IN NATURE, IF THE SYSTEM IS STABLE, THE OSCILLATIONS WILL BE DAMPED.

THE SYSTEM IS SAID TO BE STABLE IN WHICH SYNCHRONOUS MACHINES, WHEN PERTURBED, RETURN TO THEIR ORIGINAL STATE OR ANOTHER STATE ASYMPTOTICALLY WITHOUT LOSING SYNCHRONISM

THE TRANSMISSION SYSTEM SHALL BE STABLE AFTER ONE OF FOLLOWING DISTURBANCES

765 Kv LINE

i. PERMANENT 3-Φ TO GROUND FAULT; CLOSE TO THE BUS. (CLEARED IN 100ms)

ii. PERMANENT 1- Φ TO GROUND FAULT; CLOSE TO THE BUS.

SINGLE POLE OPENING(100ms) OF THE FAULTED PHASE; UNSUCCESSFUL RECLOSURE (DEAD TIME 1 s) FOLLOWED BY 3 POLE OPENING (100ms) OF FAULTED

LINE

400kV LINE

I. PERMANENT 3-Φ TO GROUND FAULT; CLOSE TO THE BUS (CLEARED IN 100ms)

II. PERMANENT 1- Φ TO GROUND; CLOSE TO THE BUS.

SINGLE POLE OPENING(100ms) OF THE FAULTED PHASE; UNSUCCESSFUL RECLOSURE (DEAD TIME 1 s) FOLLOWED BY 3 POLE OPENING (100ms) OF FAULTED

LINE

220kV/132kV

I. PERMANENT 3-Φ FAULT ON 1 CIRCUIT; CLOSE TO BUS; FAULT CLEARING TIME =160ms (8 CYCLES; ASSUMING 3-POLE OPENING)

FAULT IN HVDC CONVERTER STATION, RESULTING IN PERMANENT OUTAGE OF ONE OF THE POLES OF HVDC BIPOLE.

UNDER CONTINGENCY OF OUTAGE OF SINGLE LARGEST GENERATING UNIT OR A CRITICAL GENERATING UNIT.

3. ‘N-1-1’

FOLLOWING CONTINGENCIES UNDER ‘N-1-1’ CONDITION PERMANENT 1- Φ TO GROUND FAULT ON 400kV LINE; CLOSE TO THE BUS.

SINGLE POLE OPENING(100ms) OF FAULTED PHASE; UNSUCCESSFUL RECLOSURE (DEAD TIME 1 s) FOLLOWED BY 3 POLE OPENING (100ms) OF FAULTED LINE

TEMPORARY 1- Φ TO GROUND FAULT ON 765kV LINE CLOSE TO THE BUS . SINGLE POLE OPENING (100ms) OF FAULTED PHASE & UNSUCCESSFUL RECLOSURE ( DEAD TIME 1 s)

220kV/132kV NETWORKS, PERMANENT 3-Φ FAULT ON 1 CIRCUIT, CLOSE TO A BUS, FAULT CLEARING TIME OF 160ms (8 CYCLES; ASSUMING 3-POLE OPENING)

SUCCESSFULLY SURVIVES FOR TEMPORARY FAULT AND NOT LOSE THE SECOND ELEMENT AFTER FAULT CLEARING

LOSES 2ND ELEMENT DUE TO FAULT CLEARING FOR PERMANENT FAULT. REACHES NEW STEADY STATE W/O LOSING SYNCHRONISM. FOR NEW STATE, SYSTEM PARAMETERS SHALL NOT EXCEED LOAD LIMITS, BUT REQUIREMENT OF LOAD SHEDDING/ RESCHEDULING OF GENERATION FOR BRINGING SYSTEM PARAMETERS WITHIN NORMAL LIMITS REQUIRED

FOR T.S CONNECTING GENERATORS OR GROUP OF GENERATORS RADIALLY WITH GRID, FOLLOWING CRITERIA: SHOULD MEET ‘N-1’ CRITERIA FOR STEADY STATE AS WELL AS

TRANSIENT STATE. FOR ‘N-1-1’ ONLY TEMPORARY FAULT IS CONSIDERED FOR RADIAL

SYSTEM. IF PERMANENT IN NATURE OR SOME PART OF GRID IS

DISCONNECTED- REST OF THE GRID APPROACHES NEW STEADY STATE W/O LOSING SYNCHRONISM. IN NEW STATE, SYSTEM SHALL NOT EXCEED EMERGENCY LIMITS.

GENERATION RADIALLY CONNECTED TO GRID

CRITERIA FOR SIMULATION AND

STUDIES

FOLLOWING POWER SYSTEM STUDIES CAN BE UNDERTAKEN

POWER FLOW STUDIESSHORT CIRCUIT STUDIESSTABILITY STUDIESEMTP STUDIES

SYSTEM STUDIES FOR TRANSMISSION PLANNING

1. CONSIDERATION OF VOLTAGE LEVEL FOR PLANNING OF ISTS,

I. THE TRANSMISSION NETWORK MODELLED DOWN TO 220kV. (FOR N.E REGION, PARTS OF UTTARAKHAND,HIMACHAL PRADESH AND SIKKIM= 132kV.)

II. GENERATING UNITS WHICH ARE STEPPED UP AT 132kV OR 110kV MAY BE CONNECTED TO NEAREST 220kV BUS THROUGH 220/132 kV TRANSFORMER FOR SIMULATION PURPOSES.

III. GENERATING UNITS SMALLER THAN 50MW WITHIN A PLANT LUMPED AND MODELED AS A SINGLE UNIT, BUT INSTALLED CAPACITY< 200MW.

IV. LOAD MAY BE LUMPED AT 220kV OR 132/110kV

FOR INTRA-STS, TRANSMISSION NETWORK MODELLED DOWN TO 66kV. STUs MAY ALSO CONSIDER MODELLING SMALLER UNITS.

POWER SYSTEM MODEL FOR SIMULATION STUDIES

2. TIME HORIZONS

SYSTEM STUDIES FOR FIRMING UP THE TRANSMISSION PLANS MAY BE CARRIED OUT WITH 3-5 YEARS.

i. ABOUT 3 YEARS FOR AUGMENTATION OF CAPACITORS, REACTORS,TRANSFORMERS ETC

ii. 4-5 YEARS FOR NEW TRANSMISSION LINES AND SUBSTATIONS

PREPARE BASE CASE MODELS CORRESPONDING TO LOAD GENERATION SCENARIOS FOR 5 YEAR HORIZON.

1. ACTIVE POWER

SYSTEM PEAK DEMANDS (STATE, REGION, NATIONAL) BASED ON LATEST ELECRIC POWER SURVEY REPORT OF CEA.

LOAD DEMANDS AT OTHER PERIODS (SEASONAL VARIATION AND MIN LOADS) BE DERIVED ON ANNUAL PEAK DEMAND AND PAST PATTERN

DURING SIMULATION, IF PEAK LOAD FIGURES ARE MORE THAN PEAKING AVAILABLE GENERATION, LOADS MAY BE ADJUSTED SUBSTATION WISE

DURING SIMULATION, IF PEAKING AVAILABILITY MORE THAN PEAK LOAD, GENETATION DISPATCHES SUITABLY REDUCED SUCH THAT INTER REGIONAL POWER TRANSFERS ARE HIGH

LOAD VARIATIONS OVER YEAR SHALL BEi. ANNUAL PEAK LOADii. SEASONAL VARIATION IN PK LOADS (SUMMER,WINTER,MONSOON)iii. SEASONAL LIGHT LOAD

SUBSTATION WISE ANNUAL LOAD DATA TO BE PROVIDED BY STU.

LOAD DEMANDS

2. REACTIVE POWER

STUs MUST PROVIDE SUBSTATION WISE MAX AND MIN DEMAND IN MW & MVAr ON SEASONAL BASIS

ELSE, LOAD POWER FACTOR AT 220kV AND 132kV 0.95 LAG (PEAK LOAD) 0.98 LAG (LIGHT LOAD)STU TO PROVIDE REACTIVE COMPENSATION TO

BRING POWER FACTOR CLOSE TO UNITY AT 132kV & 220kV.

1. ALL INDIA PEAKING AVAILABILITY CALCULATED AS PER NORMS

2. FOR NEW TRANSMISSION LINES AND SUBSTATIONS, PEAK LOAD SCENARIOS FOR SUMMER,WINTER, MONSOON SEASONS TO BE STUDIED. LIGHT LOAD SCENARIOS ALSO CARRIED OUT AS PER REQUIREMENTS

3. FOR RENEWABLE ENERGY SOURCE, SOLAR OR WIND GENERATION INJECTIONS CONSIDERED IN COMBN WITH CONVENTIONAL METHODS. INTRA-STATE GENERATING STATION OF R.E.S PURCHASING STATE MAY BE BACKED DOWN, SO THAT IMPACT OF R.E.S GENERATION IS MINIMUM

GENERATION DISPATCHES AND MODELLING

4. SPECIAL AREA DISPATCHES• THEY CORESPOND TO HIGH AGRICULTURAL LOAD WITH LOW PF• COMPLETE CLOSURE OF GENERATING STATION NEWAR A MAJOR LOAD

CENTRE

5. FOR THERMAL UNITS (COAL,GAS,DIESEL,NUCLEAR), MIN OUTPUT LEVEL TO NOT BE TAKEN LESS THAN 70% OF RATED INSTALLED CAPACITY. FOR RUNNING WITH OIL SUPPORT, UPTO 25%.

6. GENERATING UNIT TO BE MODELLED TO RUN AS PER CAPABILITY CURVE. FOR ABSENCE OF CURVE, FOLLOWING VALUES.

7. GENERATOR TO PROVIDE TECHNICAL DETAILS LIKE CAPABILITY CURVE, GENERATOR, EXCITER, GOVERNER, PSS PARAMETERS, ETC. FOR MODELLING OF THE MACHINES FOR STEADY STATE AND TRANSIENT STATE STUDIES.

1. STUDIES TO BE CARRIED OUT IN CLASSICAL METHOD, FAULT PRE FAULT VOLTAGES AND SUB TRANSIENT REACTANCE OF SYNCHRONOUS MACHINE

2. MVA OF ALL GENERATING UNIT IN PLANT TO BE CONSIDERED FOR DETERMINING MAX SC LEVEL AT VARIOUS BUSES OF SYSTEM

3. INTER WINDING REACTANCES FOR 3 WINDING TRANSFORMER TO BE CONSIDERED

4. VECTOR GROUP OF TRANSFORMER TO BE CONSIDERED DURING STUDIES.

5. SC LEVEL FOR 3-Φ TO GROUND AND 1-Φ TO GROUND TO BE CALCULATED.

6. SC LEVEL MAY BE LOW FOR LIGHT LOAD SCENARIO AS COMPARED TO PEAK LOAD SCENARIO. LEVEL VARIES WITH OPERATING CONDITIONS

SHORT CIRCUIT STUDIES

FOR LARGE INTER CONNECTED GRID, UNPREDICTABLE POWER FLOWS CAN OCCUR DUE TO IMBALANCE IN LOAD GENERATION BALANCE IN DIFFERENT PARTS OF GRID. LEADS TO OVERLOADING OF TRANSMISSION ELEMENT. SUCH SITUATIONS ARE UNAVOIDABLE AND MARGINS AT PLANNING STAGES ARE REQUIRED.

OVERLOAD CAPACITY OF TRANSMISSION LINES TO BE CONSIDERED. THERMAL LOADING LIMITS FOR LINE AND TRANSFORMER TO BE

10% AND 15% FOR INTER REGIONAL. MARGIN OF ±2% KEPT IN VOLTAGE LIMITS FOR ‘N-0’ AND ‘N-1’

PLANNING MARGINS

ALL TRANSFORMERS CONSIDERED TO BE AT NOMINAL TAPS. ON LOAD TAP CHANGER (OLTC) NOT CONSIDERED.

FOR NUCLEAR GENERATING UNITS.

ARE PERFORMED TO CALCULATE MAGNITUDE AND PHASE ANGLES OF VOLTAGE, ACTIVE, REACTIVE POWER FOR GIVEN BUS.

PLAN THE BEST OPERATION ; HELP IN ASCERTAINING THE EFFECTS OF NEW LOADS,GENERATING STATIONS; PLAN THE FUTURE EXPANSION; ESSENTIAL FOR DESIGNING A NEW POWER SYSTEM.

FOUR VARIABLES ASSOCIATED WITH EACH BUS, P,Q,V AND δ. TWO OF THE FOUR ARE KNOWN; OTHER TWO UNKNOWN, DEPENDING UPON THE TYPE OF BUS.

LOAD FLOW STUDIES

ADDITIONAL PLANNING CRITERIA

AND GUIDELINES

FOR REACTIVE POWER COMPENSATION SHUNT CAPACITORS, SHUNT REACTORS,STATIC Var COMPENSATORS, VARIABLE SERIES CAPACITOR, OTHER FACTS CONTROLLED DEVICES; APPROPRIATE STUDIES ARE DONE.

SHUNT CAPACITORS132/220kV NETWORK SHUNT CAPACITORS FOR MEETING

REACTIVE POWER REQUIREMENTS PROVIDED AT 132/220kV BUSES FOR SIMULATION.

LOAD POWER FACTOR CLOSE TO UNITY BY PROVIDING SHUNT CAPACITORS.

400/220kV OR 400/132kV OR 220/132kV (OR 66 Kv) REACTIVE POWER FLOW IS MININMUM.

REACTIVE POWER COMPENSATION

STATIC Var COMPENSATION

SVC PROVIDED TO DAMP POWER SWINGS AND PROVIDE SYSTEM STABILITY UNDER ‘N-0’, ’N-1’, ’N-1-1’ CONDITIONS

SHUNT REACTORSSIZE OF REACTORS SHOULD BE SUCH THAT UNDER

STEADY STATE, SWITCHING ON AND OFF OF THE REACTOR SHALL NOT CAUSE A VOLTAGE CHANGE EXCEEDING 5%.

STANDARD SIZE (MVAr) OF REACTORS

FIXED LINE REACTORS TO CONTROL POWER FREQUENCY TEMPORARY OVER VOLTAGE AFTER VOLTAGE REGULATION HAS TAKEN PLACE

LINE REACTORS (SWITCHABLE/CONTROLLED/FIXED) PROVIDED IF CHARGING EHV LINE IS NOT POSSIBLE WITHOUT EXCEEDING MAX VOLTAGE LIMITS.

FOR EHV SUBSTATIONS REQUIREMENTS TOTAL LOAD CATERED BY SUBSTATION OF A PARTICULAR VOLTAGE LEVEL, MVA CAPACITY, NUMBER OF FEEDERS.

IMPORTANT BECAUSE PROVIDES THE NUMBER OF SUBSTATIONS REQUIRED FOR MEETING A PARTICLUAR QUANTUM OF LOAD

FOLLOWING CRITERIS PRESENT FOR DESIGNING EHV SUBSTATION.

1. MAX SC LEVEL ON ANY BUS NOT TO EXCEED 80% OF RATED SC CAPACITY. SPLITTING OF BUS, SERIES REACTOR ETC TECHNOLOGIES MAY BE ADOPTED TO LIMIT SC CURRENT.

BREAKING CURRENT CAPACITY OF SWITCHGEAR AT DIFFERENT VOLTAGE LEVELS

SUBSTATION PLANNING CRITERIA

2. RATING OF EQUIPMENT SHAL BE SUCH THAT DO NOT LIMIT LOADING LIMITS OF SUBSTATION.

3. WHEN MAX CAPACITY OF A SUBSTASTION IS REACHED, EFFORT TO BE MADE TO CREATE NEW SUBSTATION RATHER THAN ADD TRANSFORMER CAPACITY.

4. WHILE INCREASING TRANSFORMER CAPACITY, FAULT LEVEL SHOULD BE KEPT IN CHECK

5. SIZE AND NO. OF ICTs PLANNED IN SUCH A WAY THAT OUTAGE OF ONE UNIT WOULDN’T OVERLOAD OTHER ICTs.

6. STUCK BREAKER CONDITION SHALL NOT CAUSE DISRUPTION OF MORE THAN 4 FEEDERS FOR 220kV SYSTEM AND TWO FOR 400 AND 765kV SYSTEM.

CAPACITY FACTOR RATIO OF MAX GENERATION AVAILABLE AT AN AGGREGATION PT. TO THE ALGEBRAIC SUM OF EACH WIND MACHINE/SOLAR PANEL CONNECTED TO THAT GRID POINT.

THERMAL LINE LOADING LIMIT OF LINES CONNECTED TO WIND MACHINE TO BE CONSIDERED AT MAX 12KM/H SPEED.

POWER FACTOR FOR WIND AND SOLAR PLANTS 0.98

ADDITIONAL CRITERA FOR WIND AND SOLAR PROJECTS

CONSIDER TWO INDEPENDENT SOURCES OF POWER SUPPLY FOR PROVIDING START UP POWER.

ANGLE BETWEEN START UP POWER SOURCE AND GENERATION SWITCHYARD SHOULD BE MAX 10°.

EVACUATION SYSTEM FOR NUCLEAR POWER STATIONS BE PLANNED TO TERMINATE IT AT LARGE LOAD TO FACILITATE ISLANDING OF POWER SYSTEM DURING CONTINGENCY

ADDITIONAL CRITERIA FOR NUCLEAR POWER STATIONS

HVDC BIPOLE CONSIDERED FOR TRANSMITING BULK POWER (>200 MW) OVER LONG DISTANCE MORE THAN 700KM.

ALSO USED IN TRANSMISSION CORRIDORS THAT HAVE AC LINES CARRYING HEAVY POWER FLOWS (MORE THAN 5000MW) TO CONTROL AND SUPPLEMENT THE AC TRANSMISSION NETWORK.

RATIO OF FAULT LEVEL (IN MVA) AT ANY CPNVERTER STATION (FOR CONVENTIONAL SOURCE) TO POWER FLOW ON HVDC BIPOLE SHOULD NOT BE LESS THAN 3 UNDER ANY GIVEN SCENARIO.

GUIDELINES FOR PLANNING HVDC TRANSMISSION SYSTEM

VOLTAGE STABILITY STUDIES TO BE CARRIED BY CREATING FICTITIOUS SYNCHRONOUS CONDENSER AT CRITICAL BUSES USING LOAD FLOW ANALYSIS PROGRAM. BUS IS CONVERTED TO PV BUS IN THIS.

MVAr ABSORPTION DOES NOT INCREASE BY REDUCING VOLTAGE IT MAY ALSO BE REDUCED TOO. I.E MVAr ABSORPTION DOES NOT INCREASE FURTHER. THIS POINT CAN BE CALLED KNEE POINT OF Q-V CURVE. REPRESENTS POINT OF VOLTAGE INSTABILITY

FROM THE GRAPH, DISTANCE BETWEEN KNEE POINT AND ZERO MVAr VERTICAL AXIS. IS AN INDICATOR OF PROXIMITY TO VOLTAGE COLLAPSE.

EACH BUS TO OPERATE ABOVE KNEE POINT OF Q-V CURVE UNDER ALL CONDITIONS.

GUIDELINES FOR VOLTAGE STABILITY

FOR ZONE-3 RELAY, VALUE OF RELAY SETTING TO BE SUCH THAT IT DOES NOT TRIP AT EXTREME LOADING. HENCE TAKEN AS 120% OF THERMAL CURRENT LOADING LIMIT AND 0.9 PU VOLTAGE.

ELSE OTHER MEASURES ARE UNDERTAKEN AND VOLTAGE TO BE TAKEN AS 0.95 PU.

GUIDELINES FOR ZONE-3 SETTINGS