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

Abstract

The invention discloses a transformer bushing dielectric loss electrification detection method and system based on transient voltage disturbances, comprising the following steps: collecting and acquiring electromagnetic transient voltage signals generated by the transformer connection system to be tested; collecting the collected electromagnetic transient voltages The signal is processed to obtain the effective electromagnetic transient voltage signal data within the preset frequency range; the leakage current of the transformer bushing when the transient voltage disturbance occurs is collected; through the obtained effective electromagnetic transient voltage signal data and leakage current, the calculation is obtained The insulation dissipation coefficient of the bushing at different frequencies is used to complete the live detection of the bushing dielectric loss of the transformer to be tested. The invention collects the transient voltage signal at the guide rod at the entrance of the transformer bushing and uses it as the excitation source for the dielectric response test of the transformer bushing insulation, which can realize the live detection of the insulation state of the bushing, and can reduce the traditional power failure detection of the insulation state. Human and time costs.

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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