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Resource Category: TechTalks

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

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.

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.

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.

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.

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

Surface partial discharges (PD) in stator windings rated 6 kV and above causes bright white deposits on the stator coils, and is usually caused by poorly-made or poorly-applied partly conductive and silicon carbide coatings