In performing low-sensitivity, partial discharge (pd) testing in an open environment, several practical difficulties are experienced. The major obstacle encountered is the high ambient noise level resulting in an undesirable signal-to-noise ratio. The usual solution is to house all high-voltage test equipment and the cable under test in a shielded room to attenuate the noise sufficiently to perform the test. This paper describes new equipment that is capable of performing pd tests on cable in electrically noisy environments, without the benefit of a shielded room, resulting in savings in floor space and cost. The new shielded test systems are self-contained modules that combine all or some of the following components: power supply, high-voltage reactor, power separation filter (psf), high-voltage noise filter, and cable terminations, together with any necessary isolation transformer and power-line filters assembled and wired on a common pallet. The equipment can be configured for use with an existing power supply or as a complete system. Results of noise immunity tests on a complete system are presented.
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