Technical Guide
Testing self-powered relays with SVERKER 900
Page 31(33)
Figure 38.MTT Pre-fault and fault sequence for simulation of no presence of load before the fault (switch onto
fault) and test results.
Table below summarizes the test results:
Test Nr.
WIP-1 Operate Time
pre-fault 500 mA / 1 s
Fault 8 A
WIP-1 Operate Time
NO pre-fault
Fault 8 A
1
65 ms
88 ms
2
74 ms
76 ms
3
66 ms
88 ms
4
73 ms
89 ms
5
72 ms
88 ms
AVERAGE
70 ms
86 ms
We can conclude that the additional time required by WIP-1 to start-up is
(some 10 … 20 ms) is negligible
compared to the operate time when the load current is available before the fault.
Switch onto fault condition (or fault in unloaded feeders) does not create any noticeable extra time delay in the
relay operation.
7. Acknowledgment
The author Andrea Bonetti thanks the International Electrotechnical Commission (IEC) for permission to
reproduce Information from its International Standards. All such extracts are copyright of IEC, Geneva,
Switzerland. All rights reserved.
Further information on the IEC is available from
IEC has no responsibility for the placement and context in which the extracts and contents are reproduced by
the author, nor is IEC in any way responsible for the other content or accuracy therein.
