110kV降压变电站电气部分设计

图2.2

K110kV母线短路点1的短路计算

网络化简如图2.3：

图2.3

X?*=Xs= XL*1=0.222

Sn233?0.517?Sb100Xjs=Xmd= 0.517 (2-10)

因为Xjs=0.517〈 3 所以查表得：

I\* =1.913

I\0.2* =1.655

I?* =1.953

I1\* =1.635

Sb100Ib=

3U?b3?115= 0.502 KA SnI?0.502?233n=IbSb100=1.170 KA I\=I\*In=1.913×1.170=2.238 KA I\0.2=I\0.2* In=1.665×1.170=1.947 KA I?=I?* In=1.953×1.170= 2.285 KA I1\=I1\* In=1.635×1.170= 1.913 KA ich=2.55I\=2.55×2.238=5.707 KA ioh=1.52

I\=1.52×2.238=3.402 KA S\=3I\Un=3?2.238×110=426.384 MVA 35KV母线短路点K2的短路计算

网络化简如图2.4：

(2-11)

(2-12)

(2-13)

(2-14)

(2-15)

(2-16)

(2-17) (2-18)

(2-19)

图2.4

X1?X20.44?0.02?0222?22X?*=X3=XS=0.432 (2-20)

Sn233?0.432?100=1.007 Xjs=XmdSb因为Xjs=1.007〈3 所以查表得：

I\* =0.985

\

I0.2* =0.910

I?* =1.067

\I1* =1.003

SbIb=3Ub?1003?37=1.56 KA

Sn233?1.56?In= IbSb100=3.635 KA