Setting Of Reverse Zone; Series Compensated And Adjacent Lines - ABB RELION 670 Series Applications Manual

1MRK 504 152-UEN B
down during faults. The zone2 must not be reduced below 120% of the protected line section.
The whole line must be covered under all conditions.
The requirement that the zone 2 shall not reach more than 80% of the shortest adjacent line at
remote end is highlighted with a simple example below.
If a fault occurs at point F (as shown in figure 100, also for the explanation of all abbreviations
used), the IED at point A senses the impedance:
V
A
Z = = Z
AF AC
I
A
EQUATION302 V5 EN-US
IEC05000457 V2 EN-US
Figure 100: Setting of overreaching zone
7.1.3.4

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
blocking scheme, weak-end infeed and so on.
³
Zrev
EQUATION1525 V5 EN-US
Where:
ZL
Z2rem
In some applications it might be necessary to consider the enlarging factor due to fault
current infeed from adjacent lines in the reverse direction to obtain certain sensitivity.
7.1.3.5

Series compensated and adjacent lines

Application manual

+ + +
I I I I I
A C A C B
+ ⋅ Z + ⋅ R = Z + 1 +

CF AC
F
I I

A A
Z AC
A
I A
Z<
89 can be used to calculate the reach in reverse direction when the zone is used for
( )
× -
1.2 ZL Z rem 2
is the protected line impedance
is zone2 setting at remote end of protected line.
  
+
I I I
C C B
 ⋅ Z + 1 +  ⋅ R

C F F
F
I I
  
A A
Z CB
F
C
Z CF
I A+ I C
I C
Impedance protection
(Equation 88)
B
I B
IEC05000457-2-en.vsd
(Equation 89)
Section 7
SEMOD168247-33 v2
SEMOD168247-142 v2
181