GIS机械振动和局部放电融合检测系统研究

Research on Mechanical Vibration and Partial Discharge Fusion Detection System of GIS

气体绝缘组合开关潜在性的绝缘缺陷和机械缺陷是导致其发生故障的主要原因,因此同步检测GIS设备内部绝缘状态和机械状态,对电力系统的正常运行具有重要的现实意义。文中从GIS的实际检测需求出发,设计振动—超声融合传感器,搭建融合检测系统。系统基于小波包算法实现对融合信号的分离与去噪,并利用振动基频信号获取工频电压相位,作为局部放电PRPD(partial discharge phase distribution)谱图的相位参考信息,检测系统可综合实现振动—超声融合信号采集、调理转换、处理分析等功能。在实体GIS设备上开展了隔离开关接触不良机械振动—局部放电联合检测试验,试验结果表明GIS设备隔离开关接触不良缺陷程度越高,机械振动信号中100Hz基频分量和300Hz异常分量越大,且隔离开关严重接触不良状态下会产生600、900Hz的异常分量,并伴随有悬浮放电信号,PRPD谱图显示放电幅值稳定且较高,放电相位固定,特征明显。文中研制的振动—超声融合检测系统可实现对GIS机械振动、超声局放信号的时空同步检测,进而综合分析GIS的机械状态和绝缘状态,实现对于缺陷类型、缺陷程度的精准诊断;系统便携性强,提高了现场对于电力设备的巡检效率,为现场GIS便携式精准检测提供了新方案。

The potential insulation and mechanical defects of gas insulated substation(GIS)are the main reasons for its failure.Therefore,the simultaneous detection of the internal insulation and mechanical state of GIS equipment is of practical significance for the normal operation of power network.Based on the actual detection requirements of GIS,the vibration-ultrasonic fusion sensor is designed and a fusion detection system is set up.The system realizes the separation and de-noising of the fused signal based on the wavelet packet algorithm,and obtains the power fre-quency voltage phase by the use of vibration fundamental frequency signal of GIS as a reference information for the partial discharge phase resolved partial discharge(PRPD)spectrum.The detection system can comprehensively real-ize such functions as vibration ultrasonic fusion signal acquisition,conditioning conversion and treatment analysis.The joint detection test of mechanical vibration due due to weak contact-partial discharge of disconnector is carried out on the actual GIS equipment.The test results show that the higher degree of weak contact defect of disconnector of GIS equipment,the greater the 100 Hz fundamental frequency component and 300 Hz abnormal component in the mechanical vibration signal,and the 600 Hz and 900 Hz abnormal components will be generated in the serious weak contact state of disconnector,accompanied by the suspended discharge signal.The PRPD spectrum shows that the discharge amplitude is stable and high,the discharge phase is fixed and the characteristics are obvious.The vibration-ultrasonic fusion detection system developed in this paper can realize the time-space simultaneous detection of me-chanical vibration and ultrasonic partial discharge signals of GIS,and then comprehensively analyze the mechanical and insulation state of GIS so as to realize the accurate diagnosis of defect types and detect degree.The system has strong portability,improves the patrol inspection efficiency of power equipment at site,and provides a new scheme for portable and accurate detection of GIS at site.