ABSTRACT
Partial discharges are accompanied by electromagnetic, acoustic, thermal, and chemical phenomena. Global methods make it possible to measure the detailed properties of partial discharges in the insulation systems of HV electric machines. Electrical methods of measurement and detection of partial discharges include galvanic methods, measurement of partial discharges by current transformers, inductive and capacitive probes. Galvanic methods are among the most widely used direct methods of measuring partial discharges, as they allow the most accurate determination of the sizes of individual charges of partial discharges and their derived parameters, including the time courses of the corresponding current pulses. For precise measurements of partial discharges, the coupling capacitors are shielded by external electromagnetic shielding connected to the ground of the measuring system. Differential electromagnetic probes are mainly used to locate the occurrence of partial discharges in the stator grooves of HV electric rotating machines.
