Study on the Optical Measurement of Partial Discharge Under Impulse Voltage

In order to study the effectiveness and specific characteristics of the optical measurement of partial discharge under impulse voltage, a needle tip defect is made on a section of GIS(gas insulated switchgear) in the laboratory, applying positive lightning impulse voltage and positive operating impulse voltage, a set of detection system is built by using fluorescent optical fiber sensor, photoelectric multiplier and oscilloscope, and the noise signal is shielded by a metal box. Stepping up the voltage with 2.5kV as the unit, and recording the amplitude of the signal. The test results show that: the partial discharge signal can be detected by the optical method, and the myopia of the discharge signal shows exponential attenuation due to the fluorescence molecular lifetime effect. With the increase of the voltage, the amplitude of the discharge signal increases, and the increased value increases. The curve of the relationship between the amplitude of the discharge signal and the voltage is obtained, using the linear function and the quadratic function to fitting, the deviation is estimated. It is found that the coincidence with the curve of the quadratic function is higher, the average deviation of the five points under the lightning impulse voltage is only 5.4%, while the deviation under the operating impulse voltage is greater 33.7%. In TracePro simulation software, the test model is simulated, assuming that no breakdown occurs during the discharge, the discharge power is proportional to the square of the applied voltage. The simulation results show that the total optical flux detected by the sensor is proportional to the power of the light source, that means it is proportional to the square of the applied voltage.