Setting Of Reverse Zone - ABB RELION 670 SERIES Applications Manual

1MRK 506 369-UUS -
8.3.3.4
Line distance protection REL670 2.2 ANSI
Application manual
V I I
+
A A C
Z Z
= = +
AF AC
I I
A A
EQUATION302 V5 EN
A
I A
21
ANSI05000457 V2 EN
Figure 121: Setting of overreaching zone

Setting of reverse zone

The reverse zone is applicable for purposes of scheme communication logic, current
reversal logic, weak-end infeed logic, and so on. The same applies to the back-up
protection of the bus bar or power transformers. It is necessary to secure, that it always
covers the overreaching zone, used at the remote line IED for the telecommunication
purposes.
Consider the possible enlarging factor that might exist due to fault infeed from adjacent
lines. Equation 131 can be used to calculate the reach in reverse direction when the zone
is used for blocking scheme, weak-end infeed, and so on.
(
³ × -
Zrev 1.2 ZL Z rem 2
EQUATION1525 V5 EN
Where:
ZL is the protected line impedance
Z2rem is zone 2 setting at remote end of protected line.
In many applications it might be necessary to consider the enlarging factor due to fault
current infeed from adjacent lines in the reverse direction in order to obtain certain
sensitivity.
I I I
+ +
A C B
Z R Z
⋅ + ⋅ =
CF
F
I
A
Z AC
Z CB
F
C
Z CF
I A+ IB
IB
)
Impedance protection
  
I I
C C
1 Z 1
+ +  ⋅ + +
 
AC C F F
I
 A  
B
ANSI05000457-2-en.vsd
Section 8

I
+
B
R
 ⋅
F
I
A 
(Equation 130)
(Equation 131)
243