p-3.3 mathematical models and standards for current carrying capacity of overhad lines

8/2/2019 P-3.3 Mathematical Models and Standards for Current Carrying Capacity of Overhad Lines

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Mathematical Models andMathematical Models andStandards for Current CarryingStandards for Current Carrying

Capacity of Overhead LinesCapacity of Overhead LinesCalculationCalculation

NebojNebojaa PetroviPetrovi, Serbian Transmission System and Market Operator, Serbian Transmission System and Market OperatorNNinelinel ukalevski, Institute Mihailo Pupinukalevski, Institute Mihailo Pupin

SovjetSovjetkaka KrstonijeviKrstonijevi, Institute, Institute MihailoMihailo PupinPupin

SerbiaSerbia

DEMSEE 2009DEMSEE 2009 September 17September 17--18, 200918, 2009 Hotel Cont inent al, BelgradeHotel Cont inent al, Belgrade


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pagepage 22

DEMSEE 2009DEMSEE 2009 September 17September 17 --18, 200918, 2009 Hotel Cont inent al, BelgradeHotel Cont inent al, Belgrade

Mathemat ical Models and Standards for Cur rent Carrying Capacit yMathemat ical Models and Standards for Cur rent Carrying Capacit y ofof

Overhead Lines Calculat ionOverhead Lines Calculat ion

CONTENT OF PAPERCONTENT OF PAPER

Cont inuous cur rent carrying capacit ies andCont inuous cur rent carrying capacit ies and

short cur rent carrying capacit ies areshort cur rent carrying capacit ies aredetermined according t o temperatures ofdetermined according to temperatures of

conductors.conductors.

Cont inuous cur rent carrying capacit ies areCont inuous cur rent carrying capacit ies aredetermined lim it s of load t ransmissiondetermined lim it s of load t ransmission

overhead lines.overhead lines.


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CONTENT OF PAPERCONTENT OF PAPER

The cont inuous and shor tThe cont inuous and shor t -- t erm current carryingterm current carrying

capacit ies of t he overhead line, t hat are, also,capacit ies of t he overhead line, t hat are, also,

used for set t ing line over load protect ion, dependused for set t ing line over load protect ion, dependon allow ed conductor t emperature.on allow ed conductor t emperature.

CCalculationsalculations cont inuous current carryingcont inuous current carrying

capacit ies and shor t cur rent carrying capacit iescapacit ies and shor t cur rent carrying capacit iesare very im port ant for make decision in cont rolare very im port ant for make decision in cont rol

(dispat ching) cent re of t ransmission pow er(dispat ching) cent re of t ransmission pow er

system.system.



33Overhead Lines Calculat ionOverhead Lines Calculat ion


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I n t his paper, the result s ofI n t his paper, the result s of tt he cont inuous and shor the cont inuous and shor t -- t erm currentt erm current

carrying capacit ies of t he overhead line calculat ions employingcarrying capacit ies of t he overhead line calculat ions employing fourfour

mathemat ical models, according t omathemat ical models, according t o ::

IEEE Std. 738IEEE Std. 738--1993 Standard for Calculating the Current1993 Standard for Calculating the Current--Temperature Relationship of Bare Overhead Conductors,Temperature Relationship of Bare Overhead Conductors,

IEC 61597IEC 61597--19951995 Technical Report Type 3Technical Report Type 3 -- OverheadOverheadelectrical conductorselectrical conductors Calculation methods for stranded bareCalculation methods for stranded bareconductors,conductors,

CIGRE Study Committee 22CIGRE Study Committee 22 Working Group 12, TechnicalWorking Group 12, Technical

Brochure 207Brochure 207 ThermalThermal BehaviourBehaviour of Overhead Conductors,of Overhead Conductors,Paris, august 2002Paris, august 2002,,

IS 37 Overhead Lines with Nominal Voltages 400 kV, 220 kVIS 37 Overhead Lines with Nominal Voltages 400 kV, 220 kV

and 110 kV Continuous Current Carrying Capacitiesand 110 kV Continuous Current Carrying Capacities ElectricElectricPower Industry of Serbia 2003Power Industry of Serbia 2003





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Why did this paper w rit e ?Why did this paper w rit e ?

The t ransmission overhead line conductorThe t ransmission overhead line conductor

t emperatures calculat ion and/ or measurement ist emperatures calculat ion and/ or measurement isvery import ant for a safet y of people, vegetat ion,very import ant for a safet y of people, vegetat ion,bui ldings, equipment , economy, secur it y andbui ldings, equipm ent , economy, secur it y andreliabil it y of t ransmission pow er system.reliabil it y of t ransmission pow er system.

As an il lust rat ion, w e can recall t he black out onAs an il lust rat ion, w e can recall t he black out onAugust 2003, at USA and Canada and t he one inAugust 2003, at USA and Canada and t he one in

I t aly, on September, of t he same year.I t aly, on September, of t he same year.





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Why did this paper w rit e ?Why did this paper w rit e ?

At Italy is 28 September 2003 at 03:01 oAt Italy is 28 September 2003 at 03:01 oclock outageclock outageOHL 400 kV between from Italy and Swiss because ofOHL 400 kV between from Italy and Swiss because of

flashover on tree what is happened to cascade outagesflashover on tree what is happened to cascade outagesother transmission overhead lines 400 kV and 220 kVother transmission overhead lines 400 kV and 220 kVdue to overload (activity protection from overload) anddue to overload (activity protection from overload) andcomplete disintegration electric power system in Italycomplete disintegration electric power system in Italy(Blackout in Italy).(Blackout in Italy).

Interim Report of theInterim Report of the InvestigationInvestigation CommitteeCommittee on theon the 28 September 200328 September 2003

Blackout in ItalyBlackout in Italy,, UCTE ReportUCTE Report 27 October 200327 October 2003





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CALCULATIONSCALCULATIONS

The Serbian Transmission System and Market OperatorThe Serbian Transmission System and Market Operatorare used, according toare used, according to Internal standard, for ACSRInternal standard, for ACSR

((aluminiumaluminium conductors steel reinforced), AAC (conductors steel reinforced), AAC (aluminiumaluminiumconductors) and AAAC (conductors) and AAAC (aluminiumaluminium alloy conductors)alloy conductors)conductors, for the values ofconductors, for the values of 60 degrees C60 degrees C andand 8080degrees Cdegrees C for continuous and short current carryingfor continuous and short current carryingcapacities conductor temperatures, respectivelycapacities conductor temperatures, respectively..

For copper conductors, these values areFor copper conductors, these values are 50 degrees C50 degrees Cfor continuous andfor continuous and 70 degrees C70 degrees C for short currentfor short currentcarrying capacities.carrying capacities.





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CALCULATIONSCALCULATIONS

Beside usual calculations for daily summer and winterBeside usual calculations for daily summer and winterseason conditions, there are also results of calculationsseason conditions, there are also results of calculations

for supposed meteorological conditions for night summerfor supposed meteorological conditions for night summerand winter season, between 19:00 p.m. and 07:00 a.m.and winter season, between 19:00 p.m. and 07:00 a.m.For summer night, adopted value for air temperatureFor summer night, adopted value for air temperatureparameter isparameter is 25 degrees C25 degrees C, and the same variable for, and the same variable forwinter condition iswinter condition is 5 degrees C5 degrees C. The night conditions. The night conditionsvalues are based on the largest average valuesvalues are based on the largest average valuesapproximation for corresponding season, according toapproximation for corresponding season, according tothe available literature.the available literature.





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RESULT OF CALCULATIONSRESULT OF CALCULATIONS

Differences between continuous current carryingDifferences between continuous current carryingcapacities daily and night period for ACSRcapacities daily and night period for ACSR

conductors, are from 45 % to 100 % forconductors, are from 45 % to 100 % forsummer season, and from 20 % to 30 % forsummer season, and from 20 % to 30 % forwinter season.winter season.

Differences between continuous current carryingDifferences between continuous current carryingcapacities daily and night period for coppercapacities daily and night period for copperconductors 95 mm2 are from 85 % to 200 % forconductors 95 mm2 are from 85 % to 200 % forsummer season, and from 5 % to 30 % forsummer season, and from 5 % to 30 % for

winter season.winter season.





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DEMSEE 2009DEMSEE 2009 September 17September 17 --18, 200918, 2009 Hot el Cont inental,Hot el Cont inental,

BelgradeBelgrade



RESULTS OF CALCULATIONSRESULTS OF CALCULATIONS

For ACSR conductor 360/57 mm2, from whom the most of the 220 kVFor ACSR conductor 360/57 mm2, from whom the most of the 220 kVoverhead lines in transmissionoverhead lines in transmission power system of Serbia are made, thepower system of Serbia are made, thedifferences between continuous current carrying capacities for ddifferences between continuous current carrying capacities for day anday andnight period, in percent, are:night period, in percent, are:

from tables I and V is: (754 A/394 A

- 1) 100 % = 91,37 % summer season;

from tables II and VI is: (823 A/485 A- 1) 100 % = 69,69 % summer season;

from tables III and VI is: (833 A/498 A- 1) 100 % = 67,30 % summer season;

from tables IV and VIII is: (833 A/498 A- 1) 100 % = 54,54 % summer season;

from tables IX and XI is: (833 A/498 A- 1) 100 % = 25,67 % winter season;

from tables X and XII is: (833 A/498 A- 1) 100 % = 22,23 % winter season.


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DEMSEE 2009DEMSEE 2009 September 17September 17 --18, 200918, 2009 Hotel Cont inental,Hotel Cont inental,

BelgradeBelgrade



CONCLUSIONSCONCLUSIONS The efficient exploitation of transmission overhead lines,The efficient exploitation of transmission overhead lines,

as well as power system operation security and reliability,as well as power system operation security and reliability,are based on information of their continuous and shortare based on information of their continuous and short--term current carrying capabilities.term current carrying capabilities.

These values are determined by allowed conductorThese values are determined by allowed conductor

temperature and are different for different part of the day,temperature and are different for different part of the day,seasonseason ofofthe year, due to different meteorologicalthe year, due to different meteorologicalconditions.conditions.


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BelgradeBelgrade



CONCLUSIONSCONCLUSIONS

The significant variability in time and place, emphasize theThe significant variability in time and place, emphasize theneed for realneed for real--time approach to overhead line conductortime approach to overhead line conductorcontinuous and shortcontinuous and short--term current carrying capacities. Thisterm current carrying capacities. Thiscould be accomplished by implementing conductorcould be accomplished by implementing conductortemperature calculations into existing control systems.temperature calculations into existing control systems.

According to the results in this work, the use of IEEE and/orAccording to the results in this work, the use of IEEE and/orCIGRE mathematical models for conductor temperature onCIGRE mathematical models for conductor temperature on--line calculations, can be recommended for practical use inline calculations, can be recommended for practical use in

controlcontrol centrescentres..


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BelgradeBelgrade



RECOMMENDATIONSRECOMMENDATIONS

In 220 kV transmission network, in West Serbia, from Beograd, thIn 220 kV transmission network, in West Serbia, from Beograd, throughroughBajinaBajina BastaBasta andand PozegaPozega, to, to NisNis, the transmission overhead lines overload, the transmission overhead lines overload

protection, during the summer months, is usually blocked. By estprotection, during the summer months, is usually blocked. By establishingablishingcontinuous and short current carrying capacities for night condicontinuous and short current carrying capacities for night conditions intions insummer season, the operational security and reliability of 220 ksummer season, the operational security and reliability of 220 kVVtransmission network in West Serbia, including Reversible Hydroetransmission network in West Serbia, including Reversible HydroelectriclectricPower PlantPower Plant BajinaBajina BastaBasta in pumping regime, would increase, betweenin pumping regime, would increase, between19:00 pm to 07:00 am.19:00 pm to 07:00 am.

Nowadays, digital devices for protection transmission overhead lNowadays, digital devices for protection transmission overhead lines andines andsubstationsubstations SCADA systems with GPS devices enable to set four variouss SCADA systems with GPS devices enable to set four variousvalues for continuous and shortvalues for continuous and short--term current carrying capacity accordingterm current carrying capacity according

to different part of the day and season of the year.to different part of the day and season of the year.

p-3.3 mathematical models and standards for current carrying capacity of overhad lines

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