Impact Of Series Compensation On Protective Ied Of Adjacent Lines - ABB RELION 670 SERIES Applications Manual

1MRK 506 369-UUS -
8.1.2.10
Line distance protection REL670 2.2 ANSI
Application manual
• Series capacitor becomes nearly completely bridged by MOV when the line current
becomes higher than 10-times the protective current level (I £ 10· k

Impact of series compensation on protective IED of adjacent lines

Voltage inversion is not characteristic for the buses and IED points closest to the series
compensated line only. It can spread also deeper into the network and this way influences
the selection of protection devices (mostly distance IEDs) on remote ends of lines adjacent
to the series compensated circuit, and sometimes even deeper in the network.
V
A
Z
I
SA
~
E
A
Z
LA
A
V
B
Z I
SB
~
E
B
Z
B
ANSI06000616 V1 EN
Figure 92: Voltage inversion in series compensated network due to fault current
infeed
Voltage at the B bus (as shown in figure 92) is calculated for the loss-less system
according to the equation below.
(
= + × =
V V I jX I
B D B LB
EQUATION1998-ANSI V1 EN
Further development of equation
é
æ
I
= × + +
V jI X 1
ê ç
B B LB
è I
ë
EQUATION1999-ANSI V1 EN
X
( )
= = +
X V 0 LB
C B I
+
1 A
I
B
EQUATION2000-ANSI V1 EN
Equation 64 indicates the fact that the infeed current I
capacitive reactance in system: bigger the infeed of fault current, bigger the apparent
series capacitor in a complete series compensated network. It is possible to say that
V
D
A
-jX
C
I
F
B
LB
D
en06000616_ansi.vsd
) ( )
+ × - +
I j X X
A B LF C
63 gives the following expressions:
ù
ö
( )
× -
A X X
÷ ú
LF C
ø
û
B
X
LF
Impedance protection
p
F
×
I jX
B LB
increases the apparent value of
A
Section 8
· I ).
NC
(Equation 63)
(Equation 64)
(Equation 65)
193