Odawa Substation Outage Odawa substation outage on 5-2-11. Squirrel jumped between two phases on the source side of Viper three phase recloser. Opened high side trans-rupter. Caused entire substation to become de-energized.

Verified Cause A and B Phase Open Jumpers Squirrel jumped between A and B phase on source side of Viper recloser An arc was created between A and B phase and at the very end also arced to C phase A and B phase source side jumpers burnt off and arc extended to C phase. Next slides will show arc current and duration.

Electrical Events The fault/arc duration 2.5 seconds The fault current 3855 amps Melted A and B phase 4/0 copper jumpers Melted viper recloser bushings and case Fault duration due to trans-rupter on the 138 KV side of the substation transformer. Fault current produced was near maximum available substation current. 4/0 copper load current rating is 482 amps. Recloser was replaced with new unit. ($35,000 in damage)

Arc Flash Values Based on 3855 amps of fault current and 2.5 seconds: 15” = 25 Cal 30” = 6.2 Cal 60” = 1.5 Cal Uses IEEE 1584 standard from WindMil. Values would be similar for a fault caused by worker error

Back side of Viper recloser showing melted 4/0 copper jumpers and burnt recloser

Note close proximity between bushings/phases

View shows A and B Phase Source jumpers burnt. Burnt Phases