Switchgear and Cables

Medium voltage switchgear and distribution cables represents essential components of electrical power distribution systems.

Industry data shows that switchgear has the highest failure rates commonly found in a facilities power distribution systems and that an average outage is 261 hours.

95% of forced outages in switchgear are attributed to failures of the insulation system.

Traditional maintenance programs, which are outage based, rarely include inspections of the main bus. Continuous monitoring of partial discharge (PD) activity, provides the means to detect pending insulation failures that are not present in traditional maintenance practices.

IEEE Standard 493-1997 All Industry Equipment Type	Failure Rate/Year	Avg. Hours/Outage	Avg. Downtime Hours/Year
Switchgear - Bus Only7 Sections	0.0119	261	21.7413
Large Power Transformers	0.013	1076	13.988
MV Synchronous Motors	0.0318	175	5.565
MV Induction Motors	0.0404	76	3.0704
Cables (Below Grade) - 3000 feet	0.00613	53	0.97467
Cable Terminators (3)	0.000814	284	0.693528
Small Power Transforers	0.0025	217	0.5425
MV Circuit Breakers	0.0064	89.3	0.57152
Bus Duct - 30 feet	0.0038	128	0.4864

The key failure components of cables are the splices and terminations. 9 out of 10 failures will occur at these locations.

The same monitor used for switchgear can also provides the capability to monitor medium voltage cables in the switchyard.