Analysis of Alternative Parameters of DRM in High Voltage Circuit Breakers

What is it about?

Throughout its lifetime, high-voltage circuit breaker (HVCB) contacts suffer from inevitable degradation processes, especially during the formation of electric arcs. Highly degraded contacts can reduce the current interruption capacity and increase the chances of operational faults, which might lead to considerable financial losses. Therefore, the use of efficient evaluating techniques is a key factor to achieve systems reliability. The dynamic resistance measurement (DRM) is a technique that can be used to evaluate the degradation level of HVCB' contacts. It stands out from the usual technique, static resistance measurement, by allowing the assessment of both the main contacts and the arcing contacts (ACs). Usually, the mean resistance or the area under the DRM curve is used to estimate the AC degradation. However, DRM is a non-standardised technique and there are no specified parameters to evaluate the real wear conditions. Therefore, an analysis of alternative parameters extractible from the DRM technique is presented in this study, such as amplitude and variance of the DRM curve. The results attest the possible use of more than one parameter for the continuous evaluation of HVCB ACs, characterising the DRM as a more complete and precise diagnosis tool.

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Photo by Troy Bridges on Unsplash

Photo by Troy Bridges on Unsplash

Why is it important?

From the results obtained in this paper, it can be verified that the use of the area under the DRM curve may not be efficient in the diagnosis of some specific problems, such as the punctual degradation presented by the contacts C3 and C4. Therefore, the application of a continuous and joint evaluation with more than one diagnostic parameter can provide an accurate monitoring of the actual state of AC degradation.

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