冲击电压下典型局部放电信号的光电检测系统

摘要

脉冲高压下测量设备的局部放电是一种校验高压电气设备在冲击电压作用下绝缘性能与设备老化的有效方法。检测局部放电对于及时发现设备故障隐患、确保安全运行具有重要的实际意义。搭建了油纸绝缘气隙模型，利用光电检测方法，实现在高压端测量冲击电压下的局部放电，具有较高的响应特性。在试样高压端串入采样电阻，通过光学元件将采样电阻上的电流信号转换为光信号进行传输，降低了空间电磁干扰的影响，最后通过光电转换装置实现电流信号的采集。实验结果表明随着电压的升高，局部放电强度愈发剧烈，验证了光电检测方法在冲击电压下检测局部放电的可行性。%Partial discharge detection under impulse voltage is an effective method for monitoring the insulating prop-erties and the aging of high-voltage electric equipment.It is of great practical significance for discovering potential safety hazard in time and ensuring the safe operation of equipment.To investigate the partial discharge characteristics of the gap in oil-paper insulation model under lighting impulse voltage, we adopt the optoelectronic techniques featu-ring with high response characteristic.It has an advantage of measuring a partial discharges impulse current at the high-potential electrode with isolating the interference of the power source.It can obtain almost all the transient cur-rent flowing through the high-potential electrode and isolate the interference of the ground wire.Due to the fiber optic transmission, the system picks up less electromagnetic noise from the impulse generator.By concatenating a sampling resistor in the high-potential lead, the signal of current through the resistor is transmitted to the optical emitter.Final-ly, the photoelectric conversion device converts the light signal into the electrical signal which can be displayed on the oscilloscope.Experiment result shows that the partial discharge intensity changes dramatically with the increase of voltage.It verifies the feasibility of the optoelectronic techniques detecting PD under lighting impulse voltage.