Online frequency domain dielectric spectrum detection method for insulating bush

Abstract

The invention discloses an online frequency domain dielectric spectrum detection method for an insulating bush, and relates to the technical field of high-voltage insulating sleeve detection. The method comprises the following steps: S1, obtaining voltage and current signals at a high-voltage bush; S2, calculating a harmonic voltage and a harmonic current at the high-voltage bush; S3, calculatingthe complex capacitance of the main insulation of the bush within a certain frequency band range through the amplitude and phase relation; S4, calculating the frequency spectrum of the complex dielectric constant; S5, completing online monitoring of the frequency domain dielectric spectrum. According to the invention, the complex capacitance and the complex dielectric constant of a bushing main insulation system are calculated by using fundamental frequency and high-frequency components contained in steady-state harmonic waves; the passive online monitoring of the frequency domain dielectric spectrum of the bush can be realized without offline testing of equipment or active injection of broadband voltage signals, the problem that power frequency dielectric loss is not sensitive enough to insulation performance change is solved, and the problem that online monitoring is difficult to realize in traditional frequency domain dielectric spectrum testing is also solved.

Description

technical field [0001] The invention relates to the technical field of high-voltage insulating bushing detection, in particular to an online frequency-domain dielectric spectrum detection method for insulating bushings. Background technique [0002] The oil-immersed high-voltage insulating bushing is an important auxiliary safety device for large power transformers. It plays the role of leading the high-voltage and low-voltage leads inside the transformer from the transformer during the operation of the transformer. The high-voltage insulating bushing not only realizes the connection between the transformer and the external electrical The connection of the network also realizes the insulation effect of the transformer lead wire and the transformer shell. Under special working conditions such as electrical, thermal and mechanical stress during long-term operation of the bushing, abnormal operation of equipment or environmental factors, oil-paper insulation may suffer from dam...

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Problems solved by technology

Scholars at home and abroad have carried out a lot of research on the method and technology of frequency-domain dielectric spectrum applied to the state detection of oil-immersed power equipment, and found that the parameters of the frequency-domain dielectric response curve have good sensitivity to factors such as temperature, moisture, and aging degree. It can effectively reflect the change of the oil-paper insulation state, but the current research is limited to laboratory tests and field equipment offline tests, and it is difficult to realize the online monitoring of the insulation state in the long-term operation of power equipment

In the frequency-domain dielectric spectrum test, it is usually necessary to apply frequency-adjustable AC voltage, but it is often difficult to realize the power equipment running on-line, which is why the frequency-domain dielectric spectrum method has not been applied to the online monitoring of power equipment. The main reason

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