A Novel Approach for Continuous Monitoring of Partial Discharge Phenomena on Medium Voltage Equipments

Electrical distribution grids consist of many Medium Voltage (MV) devices, each one of them being a possible cause of fault. The demand for their increasing reliability and decreasing maintenance/replacement costs, together with the high number of installed apparatuses, is turning the focus of the condition assessment to smart solutions, integrable in networks, able to evaluate autonomously the condition of the electrical asset and, in case of anomalies, to request for man-operated support. In this paper, a novel approach to the continuous monitoring of PD phenomena in MV grids will be described. The devised solution addresses the requirements of the MV grids in that the system is non-invasive and low cost. PD data acquisition and processing systems are fully automatic, with the relevant assessment of the conditions of the MV piece of equipment. A comprehensive description of the proposed technological solution is reported, focusing mainly on the automatic acquisition and processing of PD data, automatic noise rejection and the recognition of increasing PD trend as a tool to trigger warning signals. To show the effectiveness of the proposed approach, case studies will be reported for various MV pieces of equipment, particularly on Switchgears and Ring Main Units.