61
Current reversal and weak end infeed
logic for distance protection (ZCAL)
Chapter 10
Verifying settings by secondary
injection
4.
Check that correct trip outputs and external signals are ob-
tained for the type of fault generated.
The operation time should be about the tDelay setting longer than
the carrier accelerated trip (ZCOM-TRIP or ZC1P-TRLn) previ-
ously recorded for permissive scheme communication.
5.
Repeat the procedure for other phases.
Only when ZC1P is used.
6.
Restore the forward and reverse zone timer to its original set-
ting.
3.2
Weak end infeed logic
3.2.1
WEI logic at permissive schemes
Procedure
1.
Check the blocking of the echo with the injection of a ZCOM-
CR or ZC1P-CRLn signal >40 ms after a reverse fault is ap-
plied.
2.
Measure the duration of the echoed signal by applying a
ZCOM-CR or ZC1P-CRLn carrier receive signal.
3.
Check the trip functions and the voltage level for trip by re-
ducing a phase voltage and applying a ZCOM-CR or ZC1P-
CRLn carrier receive signal.
4.
Repeat the procedure for other phases.
Only when ZC1P is used.
3.2.2
Testing conditions
Only one type of fault is sufficient, with ZCOM function. Apply three faults (one in
each phase), when ZC1P function is used. For phase L1-N fault, set these parameters:
Table 4:
Phase
I (Amps)
Phase-angle
(Deg)
V (Volts)
Phase-angle
(Deg)
L1
0
0
Set less than UPN<
0
L2
0
240
63
240
L3
0
120
63
120
