Review Incident Shin.. - authority for electricity regulation, oman

with the actual situation that arose here. The fault in this line, which led to an outage of a
load of up to 65MW, was far from being a non-credible event. The objective of this plan
should be to limit the customer outage until the circuit can be repaired and restored.
The plan for such a fault should concentrate on minimizing the duration of restoration or repair.
This includes several issues described below.
2.2.1. Locating the Fault
We understood that the operation engineer did not have a very detailed indication 6 about
the distance of the fault from the Wadi Jizzi grid station. Appropriate fault locators could
have been installed in the Wadi Jizzi grid station to assist the operation engineer to locate
the fault more precisely and provide the patrolling crew with a smaller area to search for the
fault. This would have shortened the time for finding the fault location (in this case 2.5
hours) significantly.
2.2.2. Availability of Spare Parts
Repair time of a line can be considerably reduced if all relevant spare parts are available in
good quality, quantity and close to the line. Moreover, transportation would be available as
well. We understood that spare conductors and sleeves were available at OETC, but that it
took a) time to find them and b) time to transport them because a border station had to be
passed. Spare insulators were not available at OETC at all. However, they were provided
by Civil Co 7 . Having all spare parts available within a limited distance of the event would
have reduced the time for getting spare parts to the fault location (in this case about 14
hours) significantly.
2.2.3. Repair Tools available
We understood that maintenance contractor Civil Co has no crimping tools locally available
for repairing the faulted 175 mm 2 conductors. Although not on a critical time path in this incident,
the same requirements for these tools apply as for spare parts. They should be available
in good quality, quantity and close to the line. According to the expired maintenance
6 The site-engineer assumed that the distance relay tripped in zone 1, which means that the fault should be
somewhere between 0-80% of the line length from Wadi Al Jizzi.
7 It has to be noted that in this incident there was no need to replace the poles, since they were all intact. Since
this review is about this incident only, we have not gone into detail about the availability of or repair of poles.
We note however that in the event of a broken pole, the repair would be far more complicated and lengthy than
in the current incident.
Review Incident Shinas August 2007 8 09.10.2007
vs. 2 (final)