and the real part gives the fault conductance:
1
1
1
Re
f
ref
R
Z
Z
æ
ö
=
-
ç
÷
ç
÷
è
ø
EQUATION2421 V1 EN
In the settings there are given two resistance levels:
•
RAlarm
given in Ω. If
f
Alarm
R
R
<
EQUATION2524 V1 EN
an alarm signal ALARM is given after a set delay
tAlarm
.
•
RTrip
given in Ω. If
f
Trip
R
R
<
EQUATION2523 V1 EN
a start signal START is given.
If the fault resistance is slightly below the set value
RTrip
the trip time will be about
10 s with default filter length of 1 s. If the fault resistance is estimated to 0 Ω the trip
delay will be 2 s with default filter length of 1 s. For values in between the delay will
follow linear interpolation describing the fault resistance time relation, as shown in
figure
.
Note that actual tripping time is dependent on the set parameter
FilterLength
which
has default value of 1s.
Section 7
1MRK502052-UEN B
Impedance protection
314
Technical manual
Summary of Contents for Relion REG670
Page 1: ...Relion 670 series Generator protection REG670 2 0 IEC Technical manual ...
Page 2: ......
Page 44: ...38 ...
Page 58: ...52 ...
Page 80: ...74 ...
Page 106: ...100 ...
Page 482: ...476 ...
Page 548: ...542 ...
Page 570: ...564 ...
Page 600: ...594 ...
Page 608: ...602 ...
Page 630: ...624 ...
Page 862: ...856 ...
Page 1094: ...1088 ...
Page 1226: ...1220 ...
Page 1250: ...1244 ...
Page 1297: ...1291 ...