Measurement Of Dielectric Loss Factor Of High Voltage Capacitive Apparatus Based On DSP

With the development of the national economy, the power system is beginning to be developed to ultrahigh voltage and large capacity. How to ensure the safe operation of high-voltage electrical equipment has become a key issue of the power system. So, it is very important to monitor the insulation state of high-voltage electrical equipment. Because the capacitive equipments are owing a large proportion in substations and power plants, simultaneously, the dielectric loss factor tanδis a significant parameter which can reflect the insulating condition of high voltage capacitive equipment. By measuring tanδ, the insulation moistened, deterioration and local defects can be found to ensure the safe operation of power system.This paper analyzed some research methods and applical situation, and designed a measuring system for the stability and precision demands in dielectric loss factor measurement. The system uses the harmonic analysis method to calculate the dielectric loss factor, and the quasi-synchronous algorithm is adopted in order to reduce the error caused by non-synchronous sampling.The system is developed with the TMS320F2812 DSP as the core of data processing and logic controlling. The AD7657 A/D converter is used for the data sampling, and the other parts of the hardware circuits are designed too. For the software, the following function is realized such as data sampling, data calculation, input and output and so on.Shown by the simulation and experiment results, using the quasi-synchronous algorithm and harmonic analysis method to measure the dielectric loss factor has the advantages of high accuracy and better anti-interference characters.