ABB REL650 - Calculating Settings for Zone 4

The reactance of the longest line adjacent out from substation B is 20 Ω as shown in figure.
The reactance of the transformer in substation B is 30 Ω (60 MVA transformer, 10 % short
circuit voltage).
The minimum reactive reach is can approximately be calculated as:
, ,
max
,
1
3.2 8 17.5
3 30 30 269
3.2
source B source A A B
Fault
A B source B
X X X
I
X X
I X
-
-
+ +
+ +
³ = × = × »
W
GUID-31F3856D-DE92-49BA-B597-6B1AA2461123 V1 EN (Equation 15)
This corresponds to 21 times the line reactance.
( )
2
2
min
,max
0.9 138
0.8 85.7
180
ext
V
R
P
×
£ × = = W
GUID-308720CF-145F-4ECB-B8F0-9142BB838613-ANSI V1 EN (Equation 16)
1. Set DirModeZ3 to Forward.
2. Set MhoCharZ3 to Directional, if CharPGZ3 and CharPPZ3 is set to Mho.
3. Set Z3 to 368 Ω
Z3 = 21 · Z
Line,posseq
= 21 · 17.5 = 368 Ω
4. Set RFPP3 to 150 Ω, if CharPPZ3 is set to Quadrilateral.
RFPP3 ≈ 0.5 · Z3 setting is proposed
5. Set RFPG3 to 150 Ω, if CharPGZ3 is set to Quadrilateral.
RFPE3 ≈ 0.5 · Z3 setting is proposed
6. Set OpModetPGZ3 to Enabled.
Zone 3 phase to earth loop gives trip.
7. Set OpModetPPZ3 to Enabled.
Zone 3 phase to phase loop gives trip.
8. Set time delays to trip
8.1. Set tPPZ3 to 0.800 s
Zone 3 phase to phase loop gives trip after a short delay.
8.2. Set tPGZ3 to 0.800 s
Zone 3 phase to ground loop gives trip after a short delay.
The time delay for zone 3 is chosen with margin to assure selectivity to zone 2 of
adjacent lines. A delay time difference of 0.4 s between the zones is sufficient. The
time delay for zone 3 is therefore chosen to 0.4 s (delay zone 2) + 0.4 s = 0.8 s.
3.1.3.5 Calculating settings for zone 4
The reach of zone 4 can be set to 85 % of the distance protection zone 1 reach of the
shortest line from A. This reactance reach is 5 Ω. This corresponds to 28 % of the reactance
of the protected line (A-B).
Section 3 1MRK 506 334-UUS A
REL650 setting examples
54
Application manual