The Realization And Methods Of Detection Of Dielectric Loss Tangent Of Capacitive Equipment

Along with the development of the power system to ultrahigh voltage and large capacity, it is highly important to monitor the insulation of device in order to ensure the safe operation of high-voltage electrical equipment.The on-line insulation monitoring is a new technology that the insulation of device is real-timely monitored under the operating voltage making up for the lack of the preventive trial.Owing to a large proportion using in substations and power plants and,simultaneously, the dielectric loss factor is a significant parameter reflecting the condition of capacitive equipment,therefore,the on-line insulation monitoring of tanδis especially important.The thesis is on the basis of it is analyzed that domestic and international various mainly lie between and decrease measurement method, the traditional wave analytic approach in harmony of key analysis examines the characteristic and produces the reason why"effect of the bar"and frequency spectrum leak from this,loss the factor in the apparatus medium of electric capacity consulting type on the basis of line detection technique,use and improve a analysis with the inserting value technology of the window.Then,use MATLAB artificial software to carry on artificial analysis.The artificial analysis results show:To the electric current sampling evenly and obtaining, voltage data adopt, would rather add Chinese window FFT algorithm analyze,in a situation that the wave,noise,electric wire netting frequency in harmony fluctuate etc.and interfere with the factor and exist,Call reduce the frequency spectrum letting out and"effect of the bar"well,enable and lie between and decrease and measure the improvement of accuracy, can be full the foot project needs.Taking into account of the environmental factors and the interference of the device circuit of its own,the device is developed with the TMS320F2812(DSP)acting as the core of data processing and logic controlling.The device is composed of signal conditioning circuit, expanded RAM,etc.As for the software,the flowing function is realized,including data sampling,analytical filtering,digital low-pass filtering, window function amending the frequency fluctuation and so on.Finally,the experiment model of the capacitive equipment is built to validate whether the designed device can effectively monitor the capacitive equipment's dielectric loss factor online.The performance of the basic approach and the modified harmonic analysis approach are analyzed by comparing the theoretical value with the two calculating method results,and the dielectric loss factor of different experimental model is monitored.The experimental results show that the device can accurately measure the dielectric loss factor.