Distributed online monitoring and positioning method of cable partial discharge based on psi-OTDR principle

Abstract

The invention discloses a distributed online monitoring and positioning method of cable partial discharge based on the psi-OTDR principle. The method comprises the following steps: establishing a cable partial discharge ultrasonic generation model, and calculating the intensity of a partial discharge ultrasonic wave; establishing a transmission model of ultrasonic waves in a cable, and calculatingultrasonic sound pressure intensity at an installation position of an optical fiber; establishing a relationship model of an ultrasonic sound pressure and optical fiber strain, and calculating a variable of sensing optical fiber strain under the action of the ultrasonic waves after the partial discharge of the cable occurs; calculating the light intensity of backward Rayleigh scattered light in the optical fiber after the partial discharge of the cable; and judging and positioning the partial discharge of the cable. By adopting the distributed online monitoring and positioning method disclosed by the invention, the distributed monitoring and positioning of partial discharge of the cable can be realized, and the abnormal discharge of the cable is reported in time, furthermore, the anti-interference ability is high, less equipment is required, the cost is low, and the monitoring method is of great significance to the safe operation of the cable.

Description

technical field [0001] The invention belongs to the technical field of cable online monitoring, and specifically relates to a -Distributed on-line monitoring and location method of cable partial discharge based on OTDR principle. Background technique [0002] Defects during the production and installation of power cables or the stress of electricity, heat, and machinery during normal operation lead to cracking of the cable insulation and partial discharge. Partial discharge will accelerate insulation cracking, induce cable failure, and seriously endanger life safety when affecting production and life. Therefore, early detection of cable partial discharge is of great significance to reduce the occurrence of cable faults, improve the reliability of power supply, and ensure the safe and stable operation of the power system. [0003] When partial discharge occurs, it is accompanied by phenomena such as electric pulses, electromagnetic waves, light emission, heat generation, u...

AI Technical Summary

Problems solved by technology

The UHF detection method is mostly used to monitor the partial discharge of transformers, GIS and cable joints. When detecting the partial discharge inside the cable, the positioning accuracy is poor. When monitoring long-distance cables, the UHF signal attenuation is serious

The ultrasonic detection method uses ultrasonic sensors, which are mostly used to monitor the partial discharge inside the transformer and GIS, and cannot detect the partial discharge of the cable in a distributed manner.

[0004] In addition, these traditional partial discharge monitoring methods are not suitable for distributed partial discharge monitoring of long-distance equipment such as cables on the one hand. On the other hand, the available monitoring methods require a large number of equipment and high monitoring costs

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