【作者】 张毓格；

【导师】 高仕斌；

【作者基本信息】 西南交通大学 ， 电力系统及其自动化， 2013， 硕士

【摘要】 随着高速铁路的快速发展,人们对牵引供电系统的安全稳定运行提出了更高要求,而牵引供电系统互感器与保护等二次设备的可靠运行则是其重要保证。分析历年来牵引供电系统的故障记录,继电保护装置不正确动作的比例居高不下,其中存在隐藏故障未及时排除是导致系统故障范围扩大的重要原因。目前,已有学者针对电力系统隐藏故障进行研究,但主要集中在对其发生概率的评估,未涉及对系统二次设备隐藏故障的诊断及状态监视等方面的研究。基于此,考虑牵引供电系统负荷变化频繁的特点,研究牵引变电所二次设备隐藏故障的在线诊断及预警具有重要意义。区别于传统故障易被发现,隐藏故障具有隐蔽、需要条件触发等特点,危害性极大。本文首先对牵引变电所二次设备隐藏故障进行分类,阐明隐藏故障与传统故障的区别,考虑利用量测值相关性原理对二次设备隐藏故障进行监测。互感器的作用是为系统检测和保护提供正确的量测值,其可靠性要求很高。当互感器开始出现隐藏故障,波形会发生畸变造成测量值不准,影响保护装置灵敏度,严重时将会影响保护选择性,导致继电保护装置的拒动或误动。本文以电流互感器(Current Transformer, CT)为例,根据基尔霍夫电流定律(KCL)联系牵引供电系统拓扑中各支路CT之间的电流约束关系建立关联矩阵,得到各CT电流解析值；再利用解析值与实测值相似系数受隐藏故障的影响规律建立投票规则,实现CT隐藏故障在线诊断。该方法基于PSCAD/EMTDC进行了仿真验证,不受系统负荷电流波动大的影响。针对不同类型故障后的电流电压特征,继电保护装置将采取不同的保护算法,对采样的测量值进行分析,并与保护整定值进行比较后选择是否动作。若测量回路中计算测量元件(如时间元件、阻抗元件等)出现隐藏故障,会直接影响保护可靠动作。本文以馈线距离保护为例,分析了复线AT和单线AT供电下,不同机车运行工况时,不同地点距离保护测量阻抗的关联关系,得到隐藏故障诊断判据,并在PSCAD/EMTDC中仿真验证了该方法的有效性。对二次设备进行在线诊断的目的是能够提前发现隐藏故障并预警,本文在最后分析了当前二次设备状态监测技术的不足,构建了牵引变电所二次设备故障预警系统框架,并重点对多信息源数据采集与处理、设备状态评估、故障预警以及维护决策支持进行了说明,为隐藏故障后续研究提供了良好的理论基础。更多还原

【Abstract】 With the rapid development of high-speed railway, a higher demand on the safe and stable operation of the traction power supply system has been put forward. Reliable operation of such secondary equipments as transformer and protection in plays an important role in traction power supply system. Analysis the traction power supply system fault records over the years, the incorrect action proportion of the protection devices stays a high level, which hidden failure not immediately removed is an important reason to cause a system failure extending. Currently, the study of power system hidden faults has been valued by some scholars, which mainly concentrated on the assessment of their probability of occurrence. The study of diagnosis and status monitoring for secondary equipments hidden fault is not involved. Based on this, considering the traction power supply system load changes frequently, researching in online diagnosis and early warning for hidden faults of traction substation secondary equipments is of importance and meaningful significance.Different from the traditional fault, hidden fault has significant harm with the feature of hidden and the need for trigger conditions. Firstly, traction substation secondary equipment hidden fault has been classified, and the difference of hidden fault and traditional fault has been clarified. Considering the secondary equipment measure values have the interrelated characteristics, hidden fault can be monitored.Transformer needs high reliability to provide the correct measurement values for detection and protection. When the transformer has hidden failure, the inaccurate measured values caused by waveform distortion will affect the sensitivity of protection, resulting in protection devices refusing to operate or mal-operating. In this paper, take the current transformer (CT) for example, according to Kirchhoff’s current law (KCL) and the traction power supply system topology, the current constraint relation between each branch of CT associated is constructed in form of matrix to obtain the analytical current value of every CT. Using the analytical and measured values of similarity coefficient to establish voting rules by the law of the impact of hidden failure to achieve CT hidden online fault diagnosis. The method is based on PSCAD/EMTDC simulation, regardless the impact of system load current fluctuation.The current-voltage characteristics of the different types of fault protection devices will take a different protection algorithms, the measured values of the sampling analysis and protection setting value is compared to choose whether or not action. That the measurement circuit measuring element such as time components and impedance element has a hidden failure will directly affect the reliability of protection. In this paper, the feeder distance protection, for example, the relationship of distance protection measure impedance has been analyzed with different locomotive operating conditions and different places of double-track AT and singlet AT power supply. The hidden fault diagnosis criterion simulation verifies its effectiveness in PSCAD/EMTDC.The purpose of secondary equipment online diagnosis is to find hidden fault and warning in advance. In this paper, the inadequate of current method of secondary device status detection has been analyzed, and the frame of traction substation secondary equipment failure warning system has been build. The study focus on multi-source data acquisition and processing technology, equipment status assessment, fault warning technology and the protection of maintenance decision-making techniques, which provides a good theoretical basis for hidden fault further study.更多还原