Transformer bushing dielectric loss live detection method and system based on transient voltage disturbance

Abstract

The invention discloses a transformer bushing dielectric loss live detection method and system based on transient voltage disturbance. The method comprises the steps of collecting and obtaining electromagnetic transient voltage signals generated by a system connected with a to-be-tested transformer; processing the collected electromagnetic transient voltage signals and obtaining effective electromagnetic transient voltage signal data in a preset frequency range; collecting and obtaining a transformer bushing leakage current when transient voltage disturbance occurs; and computing bushing insulation dissipation factors under different frequencies through utilization of the obtained effective electromagnetic transient voltage signal data and leakage current, thereby finishing bushing dielectric loss live detection of the to-be-tested transformer. According to the method and the system, the transient voltage signals at a position of a guide rod of a transformer bushing inlet is collectedand the transient voltage signals are taken as excitation sources of a transformer bushing insulation dielectric response test, so the live detection of an insulation state of a bushing can be realized, and manpower and time cost when conventional uncharged detection of the insulation state is carried out can be reduced.

Description

technical field [0001] The invention belongs to the technical field of high voltage and insulation, and in particular relates to a method and system for detecting dielectric loss and electrification of transformer bushings based on transient voltage disturbance. Background technique [0002] Since entering the 21st century, my country's national economy has developed rapidly, and the demand for electric energy in all walks of life has continued to increase rapidly, promoting the inferred expansion of the installed capacity of electric power and the scale of the power grid. Statistical analysis of the operation of the State Grid Corporation of China shows that more than 50% of grid accidents are caused by failures of power transmission and distribution equipment, and equipment problems rank first in the cause of failures. Further statistics on power equipment accidents show that oil-impregnated paper insulation equipment such as large power transformers and high-voltage bushi...

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Problems solved by technology

At present, the 10kV conventional dielectric loss test method has the following problems: first, it cannot truly reflect the condition of the equipment during operation, and it is difficult to find some internal potential defects such as weak insulation and partial discharge under high voltage; second, the insulation of the bushing is dry. 1. When the internal insulation is good, its dielectric loss basically does not change with the test voltage, but when the interior is damp, there are partial discharges or conductive impurities and other defects, the relationship between the dielectric loss and the test voltage is very large; the third is due to the high pressure of oil paper and film paper. There is a GARTON effect in all capacitors. The conventional 10kV dielectric loss test voltage is often far lower than the rated voltage, and the test results cannot truly reflect the operating conditions of the equipment. Fourth, most of the current on-site high-voltage dielectric loss tests have large test power supply capacity, The equipment is bulky, the operation is cumbersome, and it has a certain impact on the safe operation of the site and many other disadvantages; Fifth, the existing high-voltage dielectric loss can reflect limited insulation information, and cannot reflect the cause and dynamic change trend of insulation degradation

The above studies confirmed that a certain grid disturbance has the potential to be used for cable insulation detection, but did not discuss and analyze different types of disturbances and power equipment in the power system in detail

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