【作者】 徐策；

【导师】 马国明； 王浩；

【作者基本信息】 华北电力大学(北京) ， 工程硕士（专业学位）， 2021， 硕士

【摘要】 气体绝缘金属封闭输电线路(Gas Insulated Transmission Lines,GIL)设备具有距离长、全封闭的特点,一旦其发生放电故障,难以快速准确发现故障位置。现有的GIL故障检测及故障定位技术实施难度大,定位成本高。为了解决这一问题,本研究提出一种基于陡波检测的GIL故障定位系统。该系统由外部非接触式陡波传感器、信号传输线、信号采集装置、信号远程传输系统及基于电磁信号的光纤同步触发系统组成。该测量系统具有频带宽、安装方便、性能可靠等特点,满足陡波检测及故障定位的需求。首先,介绍了外部非接触式陡波传感器的测量原理,搭建了测量系统的等效电路模型,并对测量系统的频率特性进行了理论分析与标定实验。传感器基于电容分压原理。本研究将传感器测量电极与低压臂电容整合到一块印制电路板(Printed circuit board,PCB)上,有效缩小了传感器的尺寸,降低了分压器中引线上的杂散电感,避免了测量系统的高频谐振。分析了测量系统的等效电路模型,确定系统低频截止频率取决于低压臂电容与后端电路等效阻抗,高频截止频率取决于低压臂电容及其寄生电感。在实验室开展了频率响应标定试验,试验结果表明所研制传感器±3 dB范围内带宽为5 Hz～95 MHz,满足陡波信号的测量要求。其次,介绍了双端法故障定位原理,分析掌握了定位误差影响因素。搭建了模拟定位试验平台,开展了基于GPS时间同步设备的故障定位模拟实验。双端法故障定位基本原理是测量故障信号到达两端传感器的时间差。模拟定位试验结果表明,GPS时间同步设备引发的双端法故障定位误差为8.49 m～20.00 m,影响定位精度的因素为波头变缓引起的时间误差以及GPS时间同步设备的时间误差。针对GPS时间同步设备造价高昂,在短距离GIL设备故障定位时造成定位误差较大的问题,本研究开发了基于电磁信号的光纤同步触发系统。测试结果表明,所研制系统引发的双端法故障定位误差为0.78±0.50 m。最后,采用所研制的基于陡波检测的GIL故障定位系统在国内某超高压试验基地开展了故障定位测试,通过设计沿面闪络与气隙击穿两种绝缘故障类型来模拟现场故障,验证了故障定位系统的可靠性。进一步地,在国内四个500 kV变电站开展了实际测量,使用隔离开关操作产生的特快速暂态过电压(Very Fast Transient Overvoltage,VFTO)信号模拟故障陡波信号,对其放电位置进行了定位。结果表明所研制系统定位误差小于1.90 m。更多还原

【Abstract】 Gas insulated transmission lines(GIL)has the characteristics of long distance and fully enclosed.Once a discharge fault occurs,it is difficult to quickly and accurately find the fault location.The existing GIL fault detection and fault localization technology is difficult to implement,and the localization cost is high.In order to solve this problem,this research proposes a GIL fault localization system based on steep wave detection.The system consists of an external non-contact steep wave sensor,signal transmission line,signal acquisition device,signal remote transmission system and trigger system.The measurement system has the characteristics of wide frequency bandwidth,convenient installation,reliable performance,etc.,which meets the needs of steep wave detection and fault location.First,the measurement principle of the external non-contact steep wave sensor is introduced,the equivalent circuit model of the measurement system is built,and the frequency characteristics of the measurement system are theoretically analyzed and calibration experiments are carried out.The measuring sensor is based on the principle of capacitive voltage divider.This research integrates the sensor measuring electrode and the low voltage arm capacitance on a printed circuit board(PCB),which effectively reduces the size of the sensor,reduces the stray inductance on the lead in the voltage divider,and avoids the measurement system The high frequency resonance.The equivalent circuit model of the measurement system is analyzed,and it is determined that the low-frequency cut-off frequency of the system depends on the low-voltage arm capacitance and the equivalent impedance of the back-end circuit,and the high-frequency cut-off frequency depends on the low-voltage arm capacitance and its parasitic inductance.A frequency response calibration test was carried out in the laboratory.The test results show that the bandwidth of the developed sensor is 5 Hz～95 MHz within the range of ±3 dB,which meets the measurement requirements of steep wave signals.Secondly,the principle of double-ended fault localization is introduced,and the factors affecting the location error are analyzed and mastered.A simulation positioning test platform was built,and a fault localization simulation experiment based on GPS time synchronization equipment was carried out.The basic principle of double-ended fault location is to measure the time difference between the fault signal reaching the sensors at both ends.The simulated positioning test results show that the double-ended fault localization error caused by the GPS time synchronization device is 8.49 m～20.00 m.The factors that affect the positioning accuracy are the time error caused by the slowing of the wave head and the time error of the GPS time synchronization device.In view of the high cost of GPS time synchronization equipment and the large positioning error caused by the fault localization of short-distance GIL equipment,this research has developed a fiber-optic synchronization trigger system based on electromagnetic signals.The test results show that the fault localization error of the double-ended method caused by the developed system is 0.78±0.50 m.Finally,the developed GIL fault localization system based on steep wave detection was used to carry out a fault location test in an ultra-high voltage test base in China.The field fault was simulated by designing two types of insulation faults along the surface flashover and air gap breakdown,which verifies the reliability of the fault location system.Furthermore,actual measurements were carried out in four domestic 500 kV substations,and the very fast transient overvoltage(VFTO)signal generated by the operation of the isolation switch was used to simulate the fault steep wave signal,and the discharge location was located.The result shows that the positioning error of the developed system is less than 1.90 m.更多还原