光纤GIS局放超声检测系统相位反馈控制

Phase Feedback Control of Optical Fiber GIS Partial Discharge Ultrasonic Testing System

干涉型光纤超声传感是一种高灵敏度的局部放电检测方法,但其现场应用时可能受到环境中低频振动噪声的干扰,降低检测灵敏度。为此,提出了相位跟踪反馈方法,确定了反馈系统参数;然后建立了真型126k V GIS局部放电超声传感研究平台,该平台可模拟现场GIS电动力及开关动作所产生的振动噪声;最后,开展了GIS局部放电检测试验。研究结果表明:相位跟踪反馈可以补偿干涉传感系统中的相位变化,保证了传感系统灵敏度的稳定性;相位跟踪反馈方法可有效抑制由1.8 kHz以下低频噪声引发的相位衰落问题;采用相位跟踪反馈方法后,干涉型光纤超声局部放电传感系统测量灵敏度优于传统压电陶瓷传感系统,满足现场应用需求。

Interferometric optical fiber ultrasonic sensing is a high-sensitivity partial discharge detection method, but its field application may be interfered by low-frequency vibration and the noise in the environment, reducing the detection sensitivity. To this end, we proposed a phase tracking feedback method and determined the parameters of the feedback system. Then a real research platform for 126 k V GIS partial discharge ultrasonic sensor was established, which could simulate the vibration and noise generated by the on-site GIS electric power and switching actions. Finally, GIS partial discharge testing was carried out. The research results show that the phase tracking feedback can compensate for the phase change in the interferometric sensing system and ensure the stability of the sensitivity of the sensing system. The phase tracking feedback method can be employed to effectively suppress the phase fading problem caused by low-frequency noise below 1.8 kHz. After adopting the phase tracking feedback method, the measurement sensitivity of the interferometric fiber-optic ultrasonic partial discharge sensing system is superior to that of the traditional piezoelectric transducer sensing system, which meets the needs of field applications.