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Whoarewe?IPE(IndependentPowerEngineers) isanonprofitorganizationpassionateaboutthe

powerengineering industry. Ourmainmandate is to testandexpose thedifferent

issuesanddysfunctionsofdifferentpowersystemsimulationsoftwares.Pleasenote

thatallofour testsaremadeavailablealsoonYouTube for transparency.Look for

IndependentPowerEngineersonYouTubetogetaccesstoourlatestvideos.

Product ETAP

Manufacturer OTI(OperationTechnologyInc)

Version 6, 7.1, 7.5, 11,12.0 and 12.5

Revision Allversions

Operatingsystem Windows7/64Bit

Systemproperties CPU@1.80GHzRAM:2.00GB

ETAPCASE

0039

Analysis All Load Flow Methods( Adaptive Newton Raphson, Newton Raphson, Fast Decoupled,

AcceleratedGaussSeidel)

Analysisdetail Precision=0.000000001,MaxNo.ofIteration=9999

Issue Wrong results, The incoming current to a node and outgoing current from node are not

equal?

Reason WrongCalculation/ConvergencewhenR(Resistance)isHigherthanInductanceR>2X

(LVCables)

Proposedsolution none

ETAPCASE0039Overview:

Wedecided

to

remodel

an

extremely

simple

real

network

to

test

the

Load

Flow

engine

for

load

flow

in

ETAP

12.5.

Themodelconsistsofasource, twocables (Selected fromETAP library),Twosimilar inductionsmotors (Selected

fromETAPDatabase).

Figure1:SimpleNetworkmodeling

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Source(SCrating=40MVA,X/R=10,0.46KV,Isc=50KA)

Motor No.1& 2,: (0.415KV, 100 HP, PF=85.22%, Eff= 95.23%, LRC=625.4%, PF(Locked Rotor)=30.99%,

LRT=103.8%,MaxT=198.4%,Ns=1800,Nr=1782,Slip=1.02%,In=127.8A),ModelSingle2:Singlecagewithdeep

bar,H=1.44,LoadModel:TL=100w3

CableNo.1(CABLEC001):3X1C95mm2,ICEA,AL,1KV,Rubber,(R=0.37671ohm/1000m,

X=0.13884

ohm/1000

m,

Y=0.0),

Length=150m

CableNo.2(CABLEC002):3X1C35mm2,ICEA,AL,1KV,Rubber,(R=0.37671ohm/1000m,

X=0.13884ohm/1000m.Y=0.0),Length=200m

BusbarNo.1NominalVoltage:460V

BusbarNo.2and3NominalVoltages:415V

Observation

Werunloadflowinalltheloadflowmethodsandfollowingresultswillbeobtained.

Figure2:Loadflowresults,demonstratingbranchescurrents

Aboveresultswillbeobtainedwithoutanywarnings.

Doyouthinkresultsarecorrect?WejustwanttoanalysesresultsaboutBusbarsincoming/outgoingCurrents:

B002:incomingActivecurrentis259x0.869=225.07