Design On Measuring System Of Insulating Oil Dielectric Loss Based On DSP

With the rapid development of electric power enterprise,the demand on the reliability of electric power system is further more,and the development of insulation monitoring technique has been paid more attention.Oil-filled equipment plays a very important role in power system,and the dielectric loss factor(tgδ) is an important parameter to reflect the insulation condition.Therefore,studying the tgδof insulating oil is of important practical meaning.The paper introduces electric power insulation material's dielectric loss mechanism under the action of electric field, points out the major factors which influence insulating oil dielectric loss and important significance of measuring dielectric loss. expatiates on measurement principium of crossing-zero phase demodulation method,crossing-zero voltage comparison method,orthogonal synchronous separation method and freedom vector method,and points out advantages and disadvantages of these methods. Because massive harmonic interference in the electrical network, it causes signal-sampling to include the very big harmonic in the measurement system , for eliminating measurement result influence by harmonic,the paper has an in-depth study of Fourier transformation harmonics analysis measurement principle, analysis the forming reasons of frequency spectrum leakage and railing effect during measurement,achieves phase locked loop and frequency multiplier technique to realize integer-period synchronous sampling and eliminate impact of frequency spectrum leakage and railing effect in the result of measurement, and investigates in depth theory on phase locked loop and frequency multiplier technique, gives the method of realizing phase locked loop and frequency multiplier technique. for eliminating random disturbance in the measurement system of dielectric loss ,elaborates application on the theory of hard threshold value de-noise based on the wavelet transformation in the measurement system. Meanwhile, the paper analysis shortage of the methods commonly used heating insulating oil,investigate principles of traditional PID control and fuzzy control, integrats the advantage of two control algorithms, makes use of fuzzy+PID control algorithm to control insulating oil temperature, and has designed fuzzy+PID controller.Through MATLAB simulation, validates that wavelet hard threshold vale de-noise method can effectively reduce the impact of random disturbance. carries on the simulation to the controlled object...