Insulation Diagnosis Device Based On Frequency Domain Dielectric Spectroscopy Methods

Transformer is important equipment in power system, and its running state is the key to stable operation of power system. Due to our country electric power industry has made rapid development in recent years, electric power equipment especially the transformer aging problem is increasingly outstanding. Thus the transformer insulation diagnosis is necessary. The aging condition assessment of transformer still have no reliable assessment measures, relying on traditional experience assessment of transformer running state is not clearly enough to guarantee the credibility of evaluation. A large number of statistics show that the transformer fault is mainly caused by insulation degradation. Researching the transformer state detection method and the rational design of diagnostic equipment has important significance for utilization of transformer and the whole power system.This article expounds the principle of frequency domain dielectric spectrum diagnosis method, and using mathematical expression derived representation and number of characterization; At the same time using photoelectric coupler as isolation measures and high voltage cascade method to design the high voltage linear cascade amplifier as the dielectric test excitation source; By improving the common micro current test circuit, this paper designed a new type of p A level micro current measurement module. On the basis of the complete hardware circuit, this paper with the help of a data acquisition card and the LABVIEW, realizes the measurement of weak ac signal and zero phase shift filter. Under laboratory conditions on the aging oil paper insulation test, test curve of this paper can achieve similar foreign equipment standards?In this paper, the main insulation of 10 k V transformer was tested, and the measured results show that the device can be a good shielding external interference signal.