The Research And Development On The Measuring Of Digital Dielectric Loss Meter

With the improvement of the rated voltage of the electric power system, higherreliability requirements on the system power supply, so insulating performance of thesystem under normal is very important in the high field strength. Important characteristicparameters of dielectric loss angle detection is the reaction volume type equipmentinsulation condition. Therefore, the tangent of dielectric loss angle detection technologyhas great significance.This paper researches on harmonic analysis method of dielectric loss measurementalgorithm firstly, analysis reasons for the formation of spectral leakage and fence effect.For the problems in harmonic analysis, proposed correction algorithm based on tripletwindowed interpolation FFT, using the fundamental frequency near three discretespectrum amplitude accurately determine the fundamental spectral position, and then getthe fundamental amplitude and phase.By selecting the appropriate window function, and the calculation results to becorrected, even if does not meet the conditions of synchronous sampling and truncation ofthe entire cycle, calculation accuracy can meet the requirements for the measurement ofdielectric loss. For Strong electric field interference problem in the measurement ofdielectric loss and higher harmonics result to measurement, using the window functiondesign FIR digital low-pass filter to filter out the interference signal. Then, simulating andanalysising the algorithm through MATLAB. The simulation results show that the plusBlackman-Harris window spectral correction algorithm can greatly improve themeasurement accuracy of the dielectric loss, in the case of the presence of noise,measurement error absolute value is not larger than8×10^-5, and fully meet the actualmeasurement requirements of dielectric loss.This paper, regarding problems of dielectric loss measurement stability not high andthe accuracy not enough, developed a type core dielectric loss measuring deviceTMS320F2812DSP as data processing and logic control on the basis of the algorithm research, detailed given the front-end data acquisition and other functional modules designprograms and hardware circuit. Design phase locked loop frequency circuit and dual A/Dconverter, to achieve synchronous sampling of the two signals, in order to avoid the effectsof spectral leakage and picket fence effect.Therefore, further study on new algorithm of the more excellent performance, smalleraffected by harmonics, noise, grid frequency fluctuations and so on factors, using a newcombination of hardware and software measurement technology is the future focus.