eee335驱动器发电传输继电器讲座电力流巴士入场矩阵或ybuspowerflow 1eeelectures.pdf

BusAdmittanceMatrixorYbus

Firststepinsolvingthepowerflowistocreate

whatisknownasthebusadmittancematrix,

oftencalltheY.

bus

TheYbusgivestherelationshipsbetweenallthe

buscurrentinjections,I,andallthebusvoltages,

V,

I=YV

bus

TheYisdevelopedbyapplyingKCLateach

bus

businthesystemtorelatethebuscurrent

injections,thebusvoltages,andthebranch

impedancesandadmittances

Ybuample

Determinethebusadmittancematrixforthenetwork

shownbelow,assumingthecurrentinjectionateach

busiisI=IGi-IDiwhereIGiisthecurrentinjectionintothe

i

busfromthegeneratorandIDiisthecurrentflowingintothe

load

Ybuample

ByKCLatbus1wehave

−

III

1G1D1

I

1

I(withY=)

j

Z

j

=(Y+Y)V−YV−YV

AB1A2B3

Similarly

=++

IIII

2212324

=−YV+Y+Y+YV−YV−YV

()

A1ACD2C3D4

Ybuample

Wecangetsimilarrelationshipsforbuses3and4

Theresultscanthenbeexpressedinmatrixform

I=YV

bus

+−−0

I