Protection Engineering Basics and Schemes Protection Engineering | Page 248

Chapter 8
Auto reclosure
As per one estimate approximately 85% of faults occurs
in power system is transient or temporary in nature.
If we consider time than in any system there are three
types of faults
 Transient
 Permanent
 Semi-permanent
In my past organization we monthly has 156 tripping on
24 Feeder, when we traced the cause of faults many are
like that
 Bird burnt out
 Tree branch touched overhead conductors due to
fast wind
Out of 156 tripping, we found 94% tripping is transient in
nature means no fault found after complete feeder
inspection. Due to absence of transient fault mitigation
we lost
1. Approximately 200 man hour
pg. 248