Dual-principle Cable Partial Discharge Sensor and Its Data Fusion Method

Abstract

The invention discloses a double-principle cable partial discharge sensor, mainly comprising a capacitive sensor and an inductive sensor which are sleeved outside a cable shielding layer, wherein thecapacitive sensor comprises an inner layer plate, a waterproof layer and an outer layer plate in order from inside to outside, and the inner layer plate is wrapped on the outer sheath of the cable; the inductive sensor comprises an open circular coil bobbin, a coil uniformly wound on the coil bobbin, and a metal shell; the coil bobbin is made of a material with high magnetic permeability, the metal shell is disposed outside the coil bobbin; and the inductive sensor is disposed outside the capacitive sensor. A data fusion method of the sensor is also disclosed, which fully utilizes the characteristics of the dual-principle sensor with sub-band complementation and white noise uncorrelated, and combines the low-frequency / high-frequency performance of sensors with different principle to betterrestore the waveform with a frequency division weighted algorithm, thereby achieving efficient extraction of the partial discharge signal of the cable.

Description

technical field [0001] The invention relates to the field of power system automation, in particular to a dual-principle cable partial discharge sensor and a data fusion method thereof. 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 partial discharge continues, local defects in the insulation will eventually develop into a general breakdown. [0003] In the current power production, the partial discharge detection (monitoring) of cables generally adopts a regular inspection method, but the regular inspection method needs to be carried out in a power outage, and there is a difference between the offline and running status of the cable, which affects the detection accuracy, and the cable status also changes d...

AI Technical Summary

Problems solved by technology

[0008] 1) The bandwidth is relatively narrow, and the high-frequency sensitivity is insufficient. Generally, the detection sensitivity of inductive sensors is above 10pC;

[0009] 2) Based on electromagnetic coupling, the anti-interference ability is poor, and it is relatively easy to be affected by interference such as white noise and aperiodic pulse. This is the most important reason for the high false alarm rate of existing partial discharge detection, which seriously restricts the application effect

[0013] In practical applications, the main problem restricting capacitive sensors is the inconvenience of installation

Existing capacitive sensors generally cut the outer sheath of the cable, or are installed in a pre-embedded manner, which is difficult to use in existing lines

A few researchers have proposed capacitive sensors without destroying the outer sheath, but such sensors have relatively poor low-frequency response, and the sensor monitoring range is limited in field applications

But in general, due to the advantages of capacitive sensors in core performance, capacitive sensors are the current research hotspots, but the problems of installation and low-frequency signal extraction still need to be solved technically.

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