Differences between PD charges measured by Partial Discharge and Dielectric Spectroscopy systems

In some rather idealised cases, similar values of Partial Discharge (PD) apparent charge may be obtained using a PD pulse measurement system or a capacitance and loss measurement system such as Dielectric Spectro-scopy (DS). In many practical diagnostic situations, however, the results are widely different, for several possible reasons. The relative virtues of the two types of measurement are discussed here, on the grounds of useful diagnostic information. Some work on simultaneous measurement by these two methods is presented, and measurements from simple test objects are shown as examples of the factors limiting capture of the full PD charge by pulse measurement. 1