COVID-19 Corona Virus South African Resource Portal Information on Coronavirus by the World Health Organization

Resource Category: Switchgear

This TechTalk serves as an inspection and routine testing guide for switchgear, switchboard assemblies, and their associated components. It supports a predictive maintenance strategy.

Failure of electrical switchgear can cause death, severe injury and significant damage. Switchgear failure is rare, but when it occurs, the results can be catastrophic.

Electrical discharges (ED) in MV switchgear circuits are (1) Partial Discharges (PD) and (2) Partial Arcing (PA). The breakdown does not bridge the electrodes. i.e. Voids, cracks, contamination etc.

Medium voltage circuit breakers have, over recent years, seen very significant developments in both their operating function and also in the monitoring aspects of their condition.

One of the major sources of problems with circuit breakers is that caused by the deterioration of the main switching electrical contacts. The contacts in switchgear are required to provide two main functions that are mutually incompatible.

Silicon rubber vermin guards were added to seal the top part of the bushing assembly against vermin ingress.

Vacuum interrupters are used to interrupt medium voltage AC current. Depending on the construction of the vacuum circuit breaker, the bellow allows the movable contact to move while maintaining vacuum.