The Research And Development On The Measuring Of Dielectric Loss Meter Based On DsSPIC

The dielectric loss factor tand measurement of high voltage power apparatus is very important to guarantee the safety of power system running, find insulation faults in time and increase the reliability of power supply. It can find electric power equipment isolation status of damp, deteriorative change and the part bad of the small tested apparatus is transfixion or not transfixion. Therefore, the study on the tand measurement of high voltage equipment has important practical meaning.On the basis of analysis and comparison of conventional and some modern dielectric loss measurement methods in this paper, considering the difficulty consist in the dielectric loss measurement, such as the problem of the locale measurement of dielectric loss the suffering the interference of the electric field in the electrified wire net, the influence of harmonics and the leakiness of frequency spectrum due to the change of the frequency in power supply etc. a new measurement method which the frequency conversion anti-jamming technology combines the fundamental waves phase detachment method is presented.The fundamental waves phase detachment method is adopted in this design, it not only to eliminate the different-frequency interference but to can effectively restrain the influence of harmonics. For reducing the operation quantities of the fundamental waves phase detachment method, the formula of a fast arithmetic of based on the fundamental waves phase detachment method is presented and detailedly derived, it can reduce a lot of the time of measurement. Phase-Locked frequency multiplication circuit and A/D conversion unit are designed in the hardware circuit, they can simultaneous sampling integer period of two signals, thus they can avoid the spectrum leakiness and barriers effect. The method of data infrared communications is adopted, to realize the high-voltage signals' isolation transmission when using reverse-connection measurement. The circuit of gains automatic control is designed, to realize large-scale measurement, and signals' sampling precision is improved.Applying the achievement studied, it developed a dielectric loss measurement system based on microcomputer dsPIC. The results of the test indicate the measure system has many characteristics, such as the hardware circuit relatively simple, measure fast, goodanti-jamming performance and high measurement precision.