Cable partial discharge positioning method and system based on active synchronization

Abstract

The invention discloses a cable partial discharge positioning method and system based on active synchronization. The method comprises the following steps of: wrapping the outer sheath of the cable with an annular metal plate to form a coupling capacitor; covering both ends of the cable range to be tested with shielding magnetic ring to form a traveling wave boundary; injecting a high frequency pulse into the cable shielding layer as a synchronization signal through a coupling capacitor at one end of the cable range to be detected; extracting a partial discharge pulse signal and a synchronization signal at both ends of the cable range to be detected; and positioning and computing the cable partial discharge source based on the time difference of partial discharge pulse and the synchronization pulse at both ends of the cable range to be detected. The cable partial discharge positioning method and system based on active synchronization use an external annular metal plate to form a coupling capacitor to solve the problem of synchronous injection of the pulse signal, use the time difference between the synchronization signal and the cable partial discharge pulse to complete the local discharge source positioning. Compared with the traditional satellite timing synchronization and fiber synchronization method, it is convenient to implement in the field, and basically eliminates the additional error caused by time synchronization.

Description

technical field [0001] The invention relates to the field of cable partial discharge detection, in particular to a method for locating partial discharge sources of cables based on active synchronization and a system for locating partial discharge sources of cables. Background technique [0002] The cable is affected by electricity, heat and stress during long-term operation, as well as improper operation during construction and installation, which may cause local insulation defects in the cable body and accessories, and partial discharge (referred to as partial discharge). As the cable partial discharge continues, local defects will eventually develop into a breakdown of the insulation as a whole. [0003] At present, domestic and foreign research institutes have carried out a large number of cable partial discharge detection / monitoring researches, and achieved many results. Authoritative organizations such as IEEE believe that partial discharge measurement is an effective ...

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Problems solved by technology

[0008] (1) Satellite (GPS / BD) timing synchronization, satellite timing requires an external antenna, and for cable partial discharge monitoring equipment that is often installed in tunnels / cable trenches, it is difficult to lay antennas

In addition, the existing GPS / BD timing accuracy is generally at the 10ns level, which cannot fully meet the cable PD source positioning requirements

[0009] (2) The accuracy of optical fiber synchronization is high, which can reach the 1ns level, but optical fiber synchronization requires long-distance optical cables, and it is difficult to implement on-site, and the price is relatively expensive

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