System for detecting a partial discharge and a method of operating thereof

A system for detecting a partial discharge in electric power equipment, the system comprising:

• a sensor located so as to receive ultra high frequency (UHF) signals related to the partial discharge, comprising at least one antenna and at least two envelope detectors connected to at least one of said at least one antenna through respective bandpass filters;
• a measurement hub located so as to allow safe access and having a computational platform;
• the sensor and the measurement hub being interconnected by a cable;
• wherein:
• said at least one antenna is configured to derive at least two UHF signals in two different frequency bands;
• said at least two envelope detectors are configured to simultaneously detect from said at least two UHF signals respective at least two baseband signals;
• and
• said cable is configured to transmit said at least two baseband signals on corresponding at least two signal lines of said cable from said sensor to said measurement hub.

A system of 41, further comprising one or more of the following sensors:

• Temperature sensor;
• Humidity sensor;
• Dust sensor;
• Condensation sensor;
• Audible sound sensor;
• Ultrasonic PD sensor;
• Pressure sensor;
• and
• Dew point sensor.

A method of operating a system for detecting a partial discharge, the method comprising:

• (a) placing a sensor so as to receive ultra high frequency (UHF) signals related to the partial discharge, the sensor comprising at least one antenna and at least two envelope detectors connected to at least one of said at least one antenna through respective bandpass filters;
• (b) placing a measurement hub located so as to allow safe access and having a computational platform;
• (c) interconnecting the sensor and the measurement hub by a cable;
• wherein:
• (d) the step (a) comprises deriving, by said at least one antenna, at least two UHF signals in two different frequency bands;
• (e) the step (a) further comprises, by said at least two envelope detectors, simultaneously detecting from said at least two UHF signals respective at least two baseband signals;
• and
• (f) transmitting a facsimile of said at least two baseband signals on corresponding at least two signal lines of said cable from said sensor to said measurement hub.

The method of 52, further comprising:

• providing more bandpass filters than envelope detectors for said sensor, and a radio frequency switch for selecting a respective bandpass filter for each envelope detector;
• prior to the step (c), by the measurement hub, performing the following steps:
• commanding said sensor to scan available bandpass filter responses by controlling a selection of frequency bands coupled to each envelope detector by respective RF switches;
• determining the average signal noise levels for each envelope detector;
• and
• selecting a bandpass filter response from each envelope detector to provide the lowest average signal noise level for each envelope detector, provided each frequency band is used in one detector only.

The method 52, further comprising the following steps, after the step (c):

• placing built-in self-test module proximate to said sensor and connected to said measurement hub;
• by the measurement hub, commanding the built-in self-test module to output a pattern of simulated partial discharge;
• measuring a response of the system for detecting a partial discharge to said simulated partial discharge;
• and
• validating a proper functioning of the system for detecting a partial discharge based on the measured response.