Method and device for identifying insulation aging risk to cable line in distribution network

Abstract

The invention provides a method and a device for identifying the insulation aging risk to a cable line in a distribution network. The method includes the following steps: obtaining the collected values of the head-end and tail-end three-phase voltage, current, active power and reactive power of a cable line in a distribution network according to a pre-established equivalent circuit model of the cable line in the distribution network; calculating the leakage current values and the average leakage current value of the cable line within a time interval Ti of a time period T according to the collected values of voltage, current, active power and reactive power; determining the predicted leakage current value according to the leakage current values; and determining whether the cable line is inan insulation aging risk state at the current time according to the historical data and predicted data of leakage current and an insulation aging risk identification criterion. Through the technical scheme provided by the invention, the leakage current of a distribution network can be monitored and predicted in real time, an accurate warning can be given for the insulation aging risk to a cable line, and a technical support is provided for the operation and maintenance of cable lines by power grid operators.

Description

technical field [0001] The invention belongs to the field of electric power systems and automation thereof, and in particular relates to a method and a device for identifying the aging risk of insulation of distribution network cable lines. Background technique [0002] At present, my country is in a period of rapid development of the distribution network. With the increase of the distribution network scale, the user's power load level is increasing rapidly, and the requirements for the reliability of the power grid are also increasing. With the continuous increase of power load, the operating environment of power cables is becoming more and more complex, and because the cables are arranged underground and in shafts, their potential defects and aging are not easy to be found. Decreased flow rate, accelerated insulation aging, lowered insulation level, or short circuit causes power failure or even fire, which seriously spreads to other equipment, resulting in large-scale and ...

AI Technical Summary

Problems solved by technology

[0004] The current insulation aging monitoring methods mainly include DC component method, DC voltage superposition method, partial discharge method, etc.: The DC component method is easily affected by the stray current in the ground, making insulation monitoring inaccurate; the DC voltage superposition method needs to install additional At the same time, due to the influence of stray current, the measurement error is relatively large; although the partial discharge method is currently the most commonly used method in cable insulation monitoring, due to the large interference in actual monitoring, online monitoring of partial discharge is also relatively Difficulties, these methods have certain deficiencies in practical application

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