Simon Garrard’s article (‘No break of service’, EMC, September 2005, p45-46) was an excellent summary of the options available for switchgear maintenance, but I would like to expand on his discussion of partial discharge monitoring as a means of predicting equipment failure.

It is true that until relatively recently, partial discharge testing required the permanent installation of sensing equipment within the plant and was thus only appropriate to expensive or mission-critical equipment. Happily, this is no longer the case.

EA Technology has developed a portfolio of instruments for detecting, locating and monitoring partial discharge activity, both internally and on the surface of high and medium voltage assets.

The range starts with the UltraTEV, a handheld unit, which uses both ultrasonic and transient earth voltage (TEV) sensing technologies to provide an instant indication of partial discharge activity. More detailed information about the location, magnitude and frequency of partial discharge activity can then be gathered using products that are also portable. Long-term monitoring of critical equipment or whole plants is, of course, an option.

The ability to detect and monitor partial discharge activity is central to the success of condition-based maintenance regimes because, along with techniques such as live tank oil sampling and analysis, it provides the information needed to assess the condition of assets accurately. The good news is that this equipment is now more flexible and affordable.

Robert Davis, Managing Director EA Technology

Source

Electrical and Mechanical Contractor