CEA Planning Manual

8/3/2019 CEA Planning Manual

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CONTENTS

PREAMBLESCOPE. I1HILOSOPHY & GENERAL

SCENARIOS 4

789

GeneralDemands

Generation DespatchesLOADING LIMITS

STATE VOLTAGE LIMITSSTANDARDS

GeneralState Operations

Considerations ,A. Transient StabilityB. Voltage StJbility.--Steady State Oscillatory Sr;ability

.POWER COMPENSATION 12ReactorsVAR Compenstors---PLANNiNG

CRITERIA 14172123252729

PEAKING. CAPABILITY OF GENERATING STATIONS.LfNE LOADING AS FUNCTION OF LENG'fHTHERMAL LINE LOADING LIMITOPERA1'IONAL STANDARDS

ANNEX- V DATA PREPARATION FOR TI


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,+:,"~~~;'~~+.c,

PREAMBLEThe objective of system planning is to evolve a power system with a level of

adequacy and security based on

vis-a-vis acceptable degree of adequacy and security. Theon the factors such as availability of generation vis-a-vis

size and configuration of the system, control and cornmunicat.vl1

.vario~s approaches is the" acceptable system performanc~".factors affecting system performance are probabilistic in nature,

used most commonly, being rather easy to apply. For.fong operating experience and availability of reliable

namely equipment failure.Such data are presently being compiled bY a few

.Henceto adopt a deterministic approach for the present with a

.progressive adoption of probabilistic appr~ach (An Action~ , Keeping in line with the

this manual covers the planning criteria proposed to be used in.~ AC -132 kV & above and

leading to an All India Power Grid.

.is also annexed to the manual. ..~,~-,

,-,"'~~ ,~ ~"'~"C'"


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1. SCOPEThe Planning Criteria detailed herein are primarily meant for Long TelmPerspective (10 years and above) and Medium Telm (5-10 years)Transmission Planning Studies of large inter-connected power systems.t~

.2 The manual covers in detail the planning philosophy, load demands andgener.ation despatches to be considered and security standards. It alsoindicates the broad scope of system studiesand gives guide-lines for provisionof reactive compensation and for planning of substations as are relevant toperspective transm: .-;sion ystem planning. A list of definitions of telms usedin the manual is also appended.

2. PHILOSOPHY & GENERAL GUIDELINESLANNINGThe transmissior system shall be planned on the basjs ofJ'egional self-suft-iciency with'an ultimate objective of evolving a National ~ower Grid.Theregjonal self-sufficiency criteria based on load generation balance maystill dictate to have inter-regional exchanges with adequate inter-co!1nectioncapac'ity at appropriate points taking into account the topology of the twonetworks, the plant mix consideration, generation shortages due to forcedoutages, diversity in weather pattern and load fore'casting errors in eitherregions. Such inter-regional power exchanges shall also be considered inthese studies.

2.2 The system shall be evolved based on detailed power system studies whichshall include

i) Power Flow Studies


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Adoption of multi-voltage level and multi-circuit tr~lnsmission lilles

I~

The choice shall be based on cost, reliability, right-of-way requirements,energy losses. down time (in caseof upgradation and reconductoring options)etc. The adoption of existing or emerging semi conductor based technology(e.g. FACTS) in transmission upgradation may also be kept in view.

2.5 In case of generating station close to a major load centre, sensitivity of itscomplete closure with loads to be met (to the extent possible) from othergenerating stations (refer para 33.3) shall also be studied.

2.6 In case of transmission system associated with Nuclear Power Stationsthere shall be two independent sources of power supply for the purpose,ofproviding start-up power facilities:. Further the angle between sta11-uppower source and the NPP switchyard should be, as far as possible,maintained within 10 degrees.

2.7 The evacuation systetl1 or sensitive power stations viz., Nuclear PowerStatiolls, shall generally be planned so as to tennin::te it at large load centresto facilitate islanding of the power station in case of contingency.

2.8 Where only two circuits are planned tor evacuationgenerating station, these should be ( as far as possible)lines instead of a double circuit line.

of power from atwo single circuit

2.9 Rractive power flow through ICTs shall be minimal. Nom1'ally it shall notexo,'ed 10% of the rating of the ICTs. Wherever voltage on HV side of ICTis less than 0.975 pu no reactive power shall flow through ICT.

2.10 'I il~mlal/Nuclear Gelleratillg ullits shalillomlally not run at leading powerf,lctor. However, forthe purpose of charging generating unit may be allowed

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to operate at leading power factor as per the respectivt capability cUlve

Inter-regional links shall, in the present context, be planned as asynchronousties unless otherwise pelmitted from operational consideration.

LOAD-GENERATION SCENARIOSThe load-generation scenarios shall be worked out so as to reflect in apragmatic maImer the daily and seasonal variations in load demand andgeneration availability.

LOAD DEMANDS3.2.1 The profile o~'annual and daily demands will be de~ermined from past data.

These data will usually give the demand at grid supply points and for thewhole system identifying the annual and daily peak demand.

Power (MW)The system peak demands shall be based on the l,ltest reports of ElectricPower Survey (EPS) Committee. In case these pe(lk load figures aremore than the peaking availability. the loads will be suit,lbly ,ldjustedsubstation-wise to match with the availability. The load demands at otherperiods (seasonal variations and minimum loads) shall be derived b,lsed onthe annual peak demand and past pattern of lo(ld v,lri,ltiolls.

From practical considerations the load variations over the, year shall beconsidered as under:

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Annual Peak Load

Seasonal variation in Peak loads (corresponding to high themlal andhigh hydro generation)Minimum load.

Load relevant where Pumped Storage Plants are involvedor inter-regional exchanges are envisaged.

power (MVAR)power plays an impol1ant role in EHV transmission system

planning and hence forecast of reactive power demand on an area-wise orsubstation-wise basis is as mportant as active power forecast. This forecastwould obviously require adequate data on the reactive power -demands atthe different substations as well as the projected plans for reactive power

~:

For developing an optimal power system, the utilities must clearly spell out." .-'-~-~"~ ~ ~-'_:~:.-~."---' ':_~ " '~--~

.This will require compilation of past data in order to arrive ataccurate load forecast. Recognising the fact that th is data is-~ ' ." it is suggested that pending availability of such data,

load power factor at 220/132KY voltage leve!s shall be taken as..-peak load condition and 0.9 lag during light 'load conditioll

feeding predominantly agricultural loads where power factoras 0.75 and 0.85 for peak load and light load conditionsIn areas where power factor is less than the limit specified..be the responsibility of the respective utility to bring

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the providing shunt (.,-apa(.'i~()rsat

load power factor to these limits byappropriate places in the system.

GENERATION DESPATCHES3.1 Generation despatch of Hydro and Thermal/Nuclear units would be

detelmined judiciously on the basis of hydrology ,lS well as scheduledm,lintenance program of the Gener,lting Station~. The norms for workingout the peaking av,.il,lbility of difterent types of gener,lting units is givenat Annex I.ln case of nuclear units the minimum level of output sh,.ll be takenas not less th,m 70% of the rated capacity.

3.3.2 Generation despatches corresponding to the following operating conditionsSh,lll be considered depending on the n,lture ,111(\ cllal~lcteristics of t.hcsystem

Annual Peak Load

Maximum themlal generation

Maximum hydro generationAnnual Minimum Load.Special area despatches

Special de;spatches corresponding to high agricultur,1110ad witll l


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Off peak conditions with maximum pumping load wl1ere PumpedStorage stations exist and also with the inter-regional exchanges,if envisaged

Complete closure ora generating station close to a major load centre.y1

3.3.3 The generation despatch for purpose of can"ying out sensitivity studiescorresponding to complete closure of a generating station close to a majorload centre shall be worked out by increasing generation at other stations tothe extent possible keeping in view the maximum likely availability at thesestations" ownership pattenl, shares, etc.

PERMISSIBI"E LINE LOADING LIMITS.4. Pem1issible line loading limit depend on many factors such as voltageregulation, stability and cun-ent carrying capacity (thennal capacity) etc.

While Surge Impedance Loading (SIL) gives a general idea of the loadingcapability of the line, it is usual to load the short lines above SIL and long lineslower than SIL (be.causeof the stability li!'litations). S IL at different voltagelevels is given at Annex -II. Annex-II also shows line loading(in telmsofsurge"-impedance loading of uncompensated line )as a function of line lengthassuming a voltage regulation of 5% and phase angular difference of 300between the two ends of the line. In case of shunt compensated lines. the SILwill get reduced by a factor k, where

,/(l-degree of compensation)=For lin~~~~~~se permissible line loading as determined from the CUlve ishigher than the thermal loading limit, permissible loading limit shall berestricted to thelmalloading limit.

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4.2 Thennalloading limits are generally decided by design practice on the basisof ambient temperature, maximum permissible conductor temperature, windvelocity, etc. In Inqia, the ambient temperatures obtaining in the various pai1sof the country are different and vary considerably during the various seasonsof the year. Designs of transmission line with ACSR conductors in EHVsystems will nonnally be based on a conductor temperature limit of 75 (\C.However, for some of the existing lines which have been designed for aconductor temperature of 65 ()C the 10ading shall be correspondingly reduced~In the case of AAAC conductors, maximum conductor temperature limit willbe taken as 85 0 C. The maximum pennissible line loadings iri respect ofstandard sizes of ACSR and AAAC conductors employed in EHVtransmission linesfordifferent ambient temperatures and differentmaximumconductor temperatures are given in Annex -llI and the same can be followedif pennitted by stability and voltage regulation consideration.

5. STEADY STATE VOLTAGE LIMITSThe steady state voltage shall be maintained within the limits given below

Note The step change in voltage may exceed the above limits wheresimultaneous double circuit outages of400 kY lines are considered.I.n such cases it may be necessary to supplement dynamic YARresources at sensitive nodes.

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TEMPORARY OVERVOI.TAGES~!Q.-~~Q_19~d rejection.420 kV system I.S'p.u. peak phase to neu.tral ( 343 kV = I p.u.)800 kV system 1.4 p.u. peak phase to neutral (653 kV = I p.ll.)

i~ p.u. )p.u. )

SWITCHING OVERVOLTAGES )420 kV system 2.5p.u.feak phase to neutral ( 343 kY =800 kV system 1.9p.u. peak phas'e to neutral (653 kY =

~

SECURITY STANDARDS:The security standards are dictated 11Y the operational requirementsA brief write-up on the same is given at Annex -IV.

6.1

For the pllr~")I.)Sl' f transmission plannill~ the following security standardsshall be t~oll()\\!('J:

STEADY STATE OPERATION.2i) As a general rule, the EHV grid system shall be capable of

withstanding witl~out necessitating load shedding or rescheduling.ofgeneration, the follov!ing contingencies:

Outage of a 132 kY D/C line or,Outage of a 220 kY D/C line or,Outage of 400 kY single cirl'tl it line or,Outage of 765 kY single circuit line 9rOutage of one pole of HYDC Bipolar line orOutage of ,ill Interconnecting Transfonner

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The above contingencies shall be considered assuming a pre-contingency system depletion (planned outage) of another 220kY double circuit line or 400 kY single circuit line in anothercomdor and not emanating from the same substation. All thegenerating plants shall operate within their reactive capability CUlvesand the network voltage profile sh,ill also be m,iint,iined within voltagelimits specified in para 5.

ii) The power evacuation system from major generating station/complex shall be adequate to withstand outage of a 400 kV DoubleCircuit line if the ten"ain indicates such a possibility.

iii) In case of large load complexes with demands exceeding 1000 MW theneed for load shedding in theevt:ntof outageofa400kY Double circuitline shall be assessed and kept minimllm. System strengthening required,ifany, on account of this siiall be planned on an individual case-to-casebasis."

two adjacent busesv) The maximum angular separation between anyshall not norn1ally exceed 30 degrees.

STABILITY CONSIDERATIONS.3A. Transient Stability

i) The system shall remain stable under the contingency of outageof single largest unit.

ii) The system shall remain stable under the contingency of atemporary single-phase-to-ground fault on a 765 sic kV lineclose to the bus assuming single pole opening of the faulted

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phase from bo.thevds s/ in 100 msec (5 cycles) and successfulreclosure (dead time I sec).

iii) The system shall beabletosulvivea single phase-to-ground faulton a 400 kY tine close to the bus as per following criteria:-. A. 400 kV SIC line: System shall be capable of withstanding a

pelmanent fault. A~cordingly, single pole opening (100 msec) ofthe faulted phase and unsuccessful reclosure (dead time I se'c.)followed by 3-pole opening (100 msec) of the faulted line shallbe considered.

B. 400 kY D/C lime: System shall be capable of withstandinga pemlanent fault on one of the circuits when both circuits are inselvice and a transient fault when the system is already depletedwith one circuit un~ermainte1;1ance/outage. ccordingly, 3 poleopening (100 msec) of the faulted circuit shall be consideredwhen both circuits are assumed in operation (si!1gle poleopening and unsuccessful auto-reclosure is not consideredgenerally in long 400 kY D/C lines since the reclosure facility isbypassed when both circuits are in operation, due to difficultiesin sizing of neutral,grounding reactors) and single pole opening(100 msec) of the faulted phase with successful reclosure (deadtime I sec) when only one circuit is in selvice.

In case of 220/132 kY networks, the system shall be ,lble tosulvive a three-phase fault with ,l t~,lultclearing time of 160 msec(8 cycles) assuming 3-pole opelling, -~


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v) The system shall be able to sulvive a fault in HVDC converterstation resulting in pem1anent outage of one of the poles ofHVDC Bipoles

Besides the abo,,'e the s~v.\'tenlmay also he sllhjected to rare contin,gencie.\'like outage of HVDC hipole, delayed .taliit clearance mle to .\'fLlckh,"eaker condition.\' etc. The impact (~f the.\'e on .\'~vs[em tahilit~v "I(IYalso he .\'tudied H'hile workin,~ Ollt the (Iefe/lce mechanisnls ,'e(flli,'cd ins~vstem operation j'llch as load sheddin,~, ,-~eneration reschcdllli'l,~,i.\'landing, etc.

Voltage stabilityEach bus shall operate above knee point of Q- V CUlve under normalas well as the contingency conditions as discussed above in para 6.2.

c. Steady State Oscill


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from high voltage system to the low voltage system. In the cases wherenetwork below .132/220 kV Voltage level IS not represented in the systemplanning studies, the shunt capacitors required for meeting the reactivepower requirements of loads shall be provided at the .132/220kV buses.

7.2 Shunt ReactorsSwitchable re:actors shall be provided at EHV substations for controllingvoltages within the limits defined in the Para 5 without resorting toswitching-off of lines. The size of reactors should be such mat under steadystate condition, switching on and off of the reactors shall not causea voltage change exceeding 5%. The standard sizes (MVAR) of reactors are

7.2.2 Fixed line reactors may be provided to control Temporary PowerFrequencyovervoltage [after all voltage regulation action has taken place]within the limits as defined in para 5 under all probable operating conditions.

7.2.3 Line reactors (switchable/controlled /fixed) may be provided if it is .notpossible to charge EHV line without exceeding the voltage limits definedin para 5. The: possibility of reducing pre-charging voltage of the chargingend shall also be considered in the context of establishing the need forreactors.Static VAR Compens~ltion (SVC).3Static Var Compensation shall be provided where found necessary o dampthe power swings and provide the system stability under conditions defined

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in the para 6 on "Security Standards ". The dynamic range of staticcompensators shall not be utilized under steady state operating condition asfar as possible.

SUB-STATION PLANNING CRITERIA18. The requirements in respect ofEHV sub-stations in a system such as he total

load to be catered by the sub-station of a particular voltage level, itsMV A capacity, number of feeders pelmissible etc. are impol1ant to ~heplanners so as to provide an idea to them about the timt' for going in forthe adoption of next higher voltage level sub-station and also the number ofsubstations required for meeting a particular quantum of load. Keeping thesein view the following criteria have been laid down for planning an EHVsubstation:

8.2 The maximum fault level on any new substation bus should not exceed8u % of the rated rupturing capacity or the circuit breaker. The 20% marginis intended to take care ot" the increase in short-circuit levels as he systemgrows. The rated breaking current capability of switchgear at different voltagelevels may be taken as

83 Higher breaking current capability would require major design change inthe tenninal equipment and shall be avoided as far as possible.

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X.4 The capacity of any single sub-station at different voltage levels shall notnonnallyexceed :

Size and number of interconnecting transformers (ICTs) shall be planned insuch a way that the outage of any single unit would not over load the remaining

or the underlying system.

condition shall not cause disruption of more than lour feederssystem and two feeders for 400 k V system and one feeder for

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D EFINITI 0 NSSystem Elements: All switchable components of a transmission systemsuch as Transmission lines, tran~fornlers, reactors etc.

2. Contingency: Temporary removal of one or more system elements fromservice. The cause or reason for such removal may be a fault, .plannedmaintenance/repair etc.

i) Single Contingency: The contingency arising out of removal of onesystem element from service.

ii) Double Contingency: The contingency arising out of removal of twosystem elements from selvice.lt includes a D/C line, two SIC lines insame con-idor or different corridors, a SIC line and a transfolmer etc.

iii) Rare contingency: Temporar)' removal of complete g~neratingstation or complete sub-station (including all the incoming &outgoing feeders and transfolmers) from service, HVDC bipole andstuck breaker condition.

Annual Peak Load: It is the simultaneous maximum de'lnand of the systembeing studied. It is based on latest Electric Power Sl!rvey (EPS) or totalpeaking power availability, whichever is less.

4. Minimum Load: It is the expected minimum system demand and isdetei111ined from average ratio of annual peak load and minimun1 loadobserved in the system tor the last 5 years.

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Damping: A system is said to be adequately damped when halving time of

10. Oscillatory Stability: When voltage or rotor angle oscillations arepositively damped following a grid disturbance, the syste'm is said to haveoscillatory stability.I

11. Voltage.Stability: It is the ability ofasystem to maintain voltage sothat whenJoadadmittance is increased, load powerwill also increase so that both powerand voltage are controllable.

12. Transient Stability: This refers to the stability following a majordisturbance (faults. opening of a major line. tripping of a g( ilerator) andrelates to the first few swings following disturbance.

13. Temporary overvoltages: These are powerti'equency overvoltages producedin a power system due to sudden load rejection, single-'pha~)c-to -groundf1lUts, etc.

14. Switching overvoltages : These overvoltages generated Juring switching of.lines, transfonners and reactors etc. having wave fronts 250/2500rnICI'Osec.

Surge Impedance Loading: It is tile unit power factor load overa resistanceline such that series reactive loss (11X) along the line is equal to shuntcapacitive gain (yJy). Under these conditions the sending end :lnd receivingend voltages and current areequal in magnitude but different in phase position.

16. Thermal capacit}, of line: It is the amount of cun-ent that call be carried bya line conductor without exceeding its design operating temperature.

19

the least damped electro-mechanical mode of oscillation is not more than5 seconds.


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ANNEX -I(refer para 3.3.1)

PEAKING CAPABILITY OF GENERATING STATIONS.The peaking availability of generating units would be taken on the basis of the latest

nonns laid down by CEA. The spinning reseIVe of 5% for Thennal, Nuclear, Hydrogeneration and Backing down allowance of 5% for Gas based generation as laid inthe present nonns of Generation Planning Criteria of CEA may not be takeninto consideration for Transmission Planning due to continuing peaking shortage ofpower in all the regions during eighth plan period and beyond.

Nonns for peaking Capability of Thennal Stations:

The peaking capability of generating units would be computed as given below.

i),ote:

ii)

CAF= 1OO-(PMR+FOR +POR)PCF=CAF-CAF x A CIn case of Eastern and North-Eastern Regions forced outage ratewill. be ,increased by 5%.

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Norms for peaking capability of Hydro stations3%4.5 %1.0 %100 -( CM + FOR) = 92.5 %CAF -CAF x AC = 91.5 %

Norms for peaking Capability of Gas based Stations:

The gas based power stations are grouped into two categories namely base loadstations and peak load stations. The base load stations are nonnally C~ombined cyclepower plant which have Gas Turbine units and Steam Turbine units. The peak loadstations are open cycle Gas Turbines which are generally used for meeting peak loadfor about 8 Hours inadayat80% of their rated capacity. For combined cycle gas basedpower station, the peaking capability would be as given below:

Aux.consu-mption(AC)

%1.04.0

I I

CAF=J OO-(PMR+FOR+POR)PCF=CAF-CAF x AC

Note:

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Norms for peaking capability of Hydro stationsCapital Maintenance (CM) =Forced'Outage rate (FOR) =Auxiliary Consumption (AC) =Capacity availability factor (CAF) =Peaking Capability Factor (PCF) =

3%4.5 %1.0 %100 -(CM + FOR) = 92.5 %CAF -CAF x AC = 91.5 %

Norms for peaking Capability of Gas based Stations:The gas based power stations are grouped into two categories namely base load

stations and peak load stations. The base load stations are noffi1ally (~ombined cyclepower plant which have Gas Turbine units and Steam Turbine units. The peak loadstations are open cycle Gas Turbines which are generally used for meeting peak loadfor about 8 Hours in a day at 80 % of their rated capacity. For combined cycle gas basedpower station, the peaking capability would be as given below:

Note: C A F = 1 00 -(P M R + FOR + PO R )PCF=CAF-CAF x AC

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ANNEX-III(refer para 4.2)

THERMAL LOADING LIMITS

radiations = 1045W/sq.mt., Wind velocity = 2kM/hourcoeff. = 0.8, Emissivity coeff = 0.45 Age> I year

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ANNEX-IV'{ONAL Sl~NDARDSPERA'

The operational standards nonnally define the expected level of power systemperfonnance underdifferent conditions of system operations and thus provide theguiding objectives ,for the planning and design of transmission systems. In theabsence of any detailed document on operational standards, the followingobjectives are considered in the context of tonnulating the manual:The system parameters (voltage and frequency) shall be as close to the nominalvalues as possible and th'~reshall be no overloading of any system element undernormal conditions and different feasible load-generation conditions. .

The system parameters and loading of system elements shall remain withinprescribed limits and not necessitate oad shedding or generation re-schedulingin the event of outage of any single system element over and above a pre-.contingency system depletion of another element in another corridor. In the caseof 220 kV and .132~V systems this shall hold good for outage of Double Circuitlines.. n case of power evacuation from m(!jor gent1rating station/complex (whenthe terrain indicates possibilities of tower failure) the system shall withstand theoutage of two 400 kV circuits if these are 011he same tower. Also in th~ case oflarge loa9 complexes with demands exceeding 1000 MW the impact of outageof two incoming 400 kV circuits (if these are on the same towers) shall be..minImum.

3. The system shall remain in synchronism without necessitating load shedding orislandin& in the event of Single-phase-to-ground fault (three- phase fault U1 hecase of 220 kV and 132 kY systems) assuming successful clearing of fault byisol,uing/opening of the faulted system elenlent.

4. The system shall have adequate margins in terms of voltage and steady stateoscillatory stability. ~"_."5. No more than four22U kY feeders/two 400 kY feeders/one 765 kY feeder shall

be disrupted in the event of a stuck breaker situation.

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ANNEX-VDATA PREPARATION FORTRANSMISSION PLANNI'NG STUDIES

Actual system data wherever available should be used; In cases where data. s notavailable standard data given below can be assumed.I ...Load flow & Short circuit studies ...i) Load power fact9r shall be taken as per para 3.2:3 of the manual, ii) Reactive power limits for generator buses Call be taken as

Qmax = Fifty percent of active generationQrnin = (-) Fifty percent of Qmax 'iii) Desired voltage of generator (PV) buses may be taken between 1.03 and 1.05

for peak load conditions and between 0.98 to 1.0 for light load conditions.iv) Line parameters (p.u. / km / ckt at 100 MVA bas~ ),.

v) Transfoffi1er reactance Generating Unit Inter-connecting(At its own base MY A) 14-15 %. 12.5 % ,n planning studies all the traIisfoffi1ers should be kept at nominal taps and On Load Tap

Changer (OLTC) should not be considered. The effect of the taps should be kept asoperational margin. LY

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For Short circuit studies transient reactance (X'd). of the synchronous machines shallbe used. [Although sub-transient reactance rX"d) is generally lower than transientreactance and therefore short circuit levels computed using X"d shall be higher thanthol;e computed using X'd, but since circuit breaker would operate only after 100 msecfrom fault initiation, the effect of sub-transient reactance would not be present.] .For short circuit studies for asymmetrical faults vector group of tr_ansfolmers shall beconsidered. Inter-winding reactances in case of three windirig:transformers shall alsobe considered. -;For evaluating short circuit levels at generating bus ( 11 kV, 13.8 kV etc.) that unit alongwith its unit transformer shall be represcI1ted separately.Transient Stability StudiesTransicnt stability studies shall be (Jarried out on regional basis. Export/Import to/fromneighQouring region shall be represented as pass.ive oads.Voltage Dependency of the system loads

Active loads (P) shall be taken as P == Po V /V 0Reactive loads (Q) shall ,be taken as Q = Qo( V/V 0) 2Frequency Dependency of the system loads

Active loads (P) shall be taken as P = Po f/fo)Reactive loads (Q) shall be taken as independent of frequency.where Po' Q 0' V 0 and fo are values at the initial system' operating conditions

Synchronous machines may be represented as given below(for all regions except North-eastern region)

Machine Size.less than 30 MW30 to 100 MW100 to 190 MW

To be represented asmay be represented as passive loads. 'Classical model ( IEEE type 1)Transient model .( IEEE type 2 for Hydro)( IEEE type 3 for Theffi1al)Sub-transie,nt model (IEEE type 4 for Hydro)

(IEEE type 5 for Theffi1al)200 and above

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TYPICAL PARAMETERS FO~HERMAL & HYDRO MACHINESMACHINE DATA-THERMAL/HYDRO

MACHINE RATING (MW)MACHINEPARAMETERS HYDRO200THERMAL500 210

13.80225.00

3.521.00

588.003.07

15.75247.00

2.730.160.960.65

o.2.2.

0.182.232.11

0.270.53

0.270.65

0.270.70

0.180.23

0.2120.233

0.2140.245

9.02.5

7.02.5

9.70.5

0.050.10 .""""--~

0.040.2

0.040.2

Rated Voltage (k V)Rated MV AInertia Constant (H)ReactanceLeackage (Xl)Direct axis (Xd)Quadrature axis (Xq)Transien t reactanceDirectaxis (X'd).Quadratureaxis (X' q)Sub- transient reactanceDirectaxis (X"d)Quadrature axis (X" q)OpenCircuitTime ContTransientDirectaxis (T'do)Quadrature axis (T'qo)Sub-transientDirect axis (T" do ) .Quadrature axis (T"qo)

Lrd.ource MIS Sharar Hea\')' ,

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TYPICAL PARAMETERS FOR EXCITERS

f8"~,..tI'"J8"'.

~ra.~

~

~U~,

." .1l+sTR VRmaxr-- -UF... ~~KA -~-i+STA l+sTE -

v R@!L/vs ~~~~~- L I-llL+s FI ---~.~

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--.H. V.D.C. data: No standardised DC control model has beendeveloped so far asthis model is usually built to the load requirements of the DC tenninals. Based onthe pastexperience in carrying out stability studies, he following models have beensuggested or rectifier and nvertortenninals.

DC CONTROL MODEL FOR RECTIFIER (POWER CONTROL)CURRENT ORDER REGULATORId "

CURRENT REGULATORALRX ,\LRX

~ 1=- ~:;~~ I1 ALF,\;;{~2,;-':'-! MIN ~JA.LR.N- -~ -ALR.N- - 1:-;:1;;--7 '1t

Vdi f T .1:= : = :.= : = : = .,aci TYPICALALANALRX.iTR :KTIIMNVMAXVMIN

VALUES.5900.002200.020.100.850.30

~-)10',Vacr

{MAXI~~./~VMIN VM

~~::=J-L ~ I~~

VDCOL

ALFO ALFOII +s

I: -' 'ALRxI i\LO:\"CURRENT RE(; ULA TO R

Id

CURRENT ORDER REGULATOR

D C CONTROL MODEL FOR INVERTOR33


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E.M. T.P. Studies: System shall be, to the extent possible, represented in detail. Parallelcircuits/ alternate paths shall also be considered. At least one source shall be representedas type 59 (detail representation). Saturation cliaracteristics of transt:'oi111ers.andreactors shall also be considered.';Voltage Stability Studies :These studies are calTied out using loadflow analysisprogram by creating a fictitous synchronous condenser at lllo~t voltage ~ensitivc bus i.e.:bus s converted into PV bus. By reducing desired voltage of this bus M VAR generation/absol-ption is monitored. When voltage is reduced to some level it may be obsel"Ved hatMYAR absol-ption does not increase by reducing voltage fU11her inst~ad it also getsreduced. The voltage where MY AR absorption does not increase any further is knownasKnee Point of Q- V curve. The knee point of Q- V curve represents the point of voltage

iinstability. The horizontal 'distance' of the knee point to the zero-MVAR vertical axismeasured in MVARs , is therefore an indicator of the proximity to the voltage collapse.


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CEA Planning Manual

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