A New Integrated Instrument for Partial Discharge Monitoring and Diagnostics of Medium Voltage Cables

The main features of a new integrated instrument designed for Partial Discharge (PD) monitoring and diagnostics of Medium Voltage (MV) cables, are summarized in this paper. The instrument is based on a multi-channel acquisition system that allows monitoring the PD activity in a given number of tested objects or couplers, after prefixed time-intervals by selecting individually the input channels using the “daisy-chain” technique. After acquisition, pulse-signals are first separated in classes according to their shape by means of the OPTICS clustering algorithm. Each class is successively organized in the so-called Phase Recorded PD (PRPD) patters and each sub-pattern is analyzed to distinguish noise (to be rejected) or PD. A fuzzy-logic inference engine is employed to identify the defect typology that support the discharge phenomenon. A short description of the integrated instrument is presented in this paper that include some analyzes acquisition and processing of PD occurring in a real MV cable. The integrated PD instrument has been designed to be utilized by a non-particularly skilled operator.