The role of DC voltage endurance test in the cable fault nature determination

Abstract

In determining the nature of the cable fault, the combination method of insulation resistance and conduction tests now commonly be used. Proven through long-term practice, there are some limitations and the one-sidedness of this method. For some leakage or flashover high impedance faults, in order to further determine the nature of the faults, DC voltage test must be applied on the basis of the above. When the intermittent earthing signal of the operating cable occurs or the grounding insulation resistance greater than 5MΩ, the DC voltage test should be used to determine the nature of the fault. Through the leakage and flashover fault formation principles, the nature of the cable fault not only can be accurately determined, pre-applied voltage value can also be provided for rough positioning by the DC endurance voltage endurance test.