Online inspection method of three-phase cross interconnected electric cable intermediate head partial discharge

Abstract

The invention relates to an online inspection method of three-phase cross interconnected electric cable intermediate head partial discharge. The online inspection method of the three-phase cross interconnected electric cable intermediate head partial discharge comprises the following steps of (1) connecting three capacitive sensors with bolts, (2) connecting the three capacitive sensors with cable cores, (3) connecting the cable cores with detecting impedance, (4) connecting three pieces of detecting impedance and the outer skin of sensor electric cables and connecting the three pieces of detecting impedance and the outer skin of the sensor electric cables with the ground, (5) connecting the three pieces of detecting impedance with protective gaps in parallel, (6) connecting the detecting impedance with bayonet nut connectors (BNC), (7) connecting the BNC connectors with a oscilloscope, and (8) judging whether the electric cables have partial discharge through the oscilloscope. The online inspection method of the three-phase cross interconnected electric cables intermediate head partial discharge has the advantages of being used in detection when the electric cables run online, free from influences on power supply of a circuit, enabling the capacitive sensors and the detecting impedance to be installed in a interconnection box, only three measuring electric cables to be led out of the BNC connectors on the outer wall of the interconnection box in measurement and the measurement to be convenient, being safe and reliable, enabling a user to observe graphic information of detection signals directly through the oscilloscope and being capable of judging whether the electric cables have the partial discharge.

Description

technical field [0001] The invention relates to an on-line detection method for the partial discharge of the middle joint of a three-phase cross-interconnection cable, in particular to a method for on-line detection of the partial discharge at the middle joint of a three-phase cross-interconnection cable with a capacitance sensor. Background technique [0002] At present, the on-line partial discharge detection of cables at home and abroad has developed from the traditional IEC60270 detection method to today's VHF (very high frequency) frequency band and even to the detection of UHF (ultra high frequency) frequency band, especially the detection of VHF (very high frequency) Detection is well established, but is based on the detection of pulsed current measuring coils in the vicinity of cable joints. For direct-buried cables, since only the cross-connection box is exposed on the ground, it is far away from the cable joint, and there is no good detection method. [0003] The ...

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Problems solved by technology

[0004] The purpose of the present invention is to provide an on-line detection method for the partial discharge of the middle joint of the three-phase cross interconnection cable, so as to overcome the shortcomings that the partial discharge of the directly buried cable cannot be detected by the current detection of the partial discharge of the cable

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