•
Delay (1) < Delay (2) < Delay (3) < Delay (4) < Delay(Def)
•
Delay (OR) < Delay (2)
When grading the operating times of several distance relays, the minimum grading time
should not be less than the sum of the circuit-breaker operating time plus 150 ms (reset time +
operating time of the measuring safety margin).
Recommended timer settings:
•
Zone 1: normally instantaneous
•
Zone 2:
Delay (2) is normally set to the sum of relay and circuit breaker operating times,
arc extinction time, signal transmission time and a tolerance margin, which amounts to
about 0.25 to 0.5 s. The tolerance includes an allowance for sequential trip-ping.
•
Zone 3:
Delay (3) is set to about 2 × Delay (2).
•
Zone 4:
Delay (4) or Delay(Def) is normally set to at least 4 × Delay (2).
Special cases may require settings, which deviate considerably from the above
recommendations.
The time steps of zones (1 to 4) must have settings less than
Delay(Def).
5.1.6.4
Definitive zone (Def)
GUID-42A75BFC-871D-41BB-A9C0-327B47EE2AB2 v1
The definitive (or fifth) zone is subject to the same parameters as the underimpedance
starters (that is,
XA, XB, RA, RB, RLoad and AngleLoad).
The corresponding time step is defined by the parameter
Delay (Def).
18000011-IEC19000413-1-en.vsdx
X
Load Angle
XA
-XB
RA
-RB
RLoad
-RLoad
R
27
o
27
o
(In tripping
direction)
IEC19000413 V1 EN-US
Figure 12: Definitive zone characteristic
1MRK 505 406-UEN B
Section 5
Bay protection functions
Bay protection functions REB500
47
Technical manual
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