Study on the On-line Dielectric Loss Tangent Monitoring Technique of Capacitive-Type Equipment

摘要

In this paper, a new style digital instrument of on-line detecting dielectric was designed according to the principle of frequency conversion and harmonic analysis. The instrument is made up of SCM model AT89C51, high-voltage conversion inversion power sources, analog-digital converter model AD7862 and so on. The AT89C51 CPU, which is the core of the measuring system, can achieve frequency control of variable-frequency power sources, data acquisition, signal pre-process, data process, tgδ calculation and display. The frequency-shift FFT technology was introduced to reduce periodicity of Fourier transform and improve SCM data-processing capacity. The results of emulation test shows that the instrument design has satisfying effect.