配电线路故障测距技术依据线路故障时的故障特征自动判明故障位置，有利于及时修复线路，保障供电可靠性。配电线路多为辐射状结构，具有供电距离短、分支多、存在架空-电缆混合输电模式、不换位等特点，使得配电线路故障测距问题远较输电线路复杂、困难；另外，由于配电线路短，如果测距误差大，就失去了测距的意义，因此要求配电线路故障测距具有高精度，遗憾的是，现有的测距方法精度不高，不能满足该要求；同时，配电网普遍采用中性点非有效接地方式，线路发生单相接地故障时，不能构成短路回路，故障信息不明显，测量故障距离更困难。因此解决配电线路故障测距问题具有重要的理论意义和实际应用价值。 论文针对中性点非有效接地系统中的配电线路相间短路故障和单相接地故障测距问题展开研究，主要工作内容如下： 针对短路故障测距，以适合于配电线路特点、提高测距精度为研究目标。首先提出了改进的阻抗测距法，该方法采用分布式参数模型有效提高了测距精度；为了更全面解决故障测距问题，还讨论了单端行波测距法和改进阻抗测距法相结合的组合测距法，重点分析了在配电线路上单端行波测距法应用的可能性和组合测距法对配电线路特有结构的适用性。 针对单相接地故障测距，以适合于配电线路特点、有效准确测距为研究目标。在基于零/线模波速度差的测距方法基础上，通过对故障波形分析和理论推导，明确了线模和零模波头正确的获取原则；为识别较缓波头的初始畸变点，提出了带陡度模极大值的波头辨识方法；考虑依频特性的影响，采用奇异性指数和峭度拟合零模波速度；为提高测距可靠性，增加了基于频带衰减相对值的辅助测距方法。 在智能配电网中，分布式电源的接入导致配电网成为双端电源网络，加大了测距难度。本文论述了前述测距方法在智能配电网中的适用性，并进一步探讨了分布式电源接入侧系统较强时双端行波故障测距方法的应用。 论文认真考虑了配电线路结构特点，提出了一套完整的配电线路故障测距方案，并在DLFLS-01系统上实现了短路故障测距、单相接地故障测距和双端故障测距功能。通过仿真测试、暂态行波测试仪试验、现场试验，全面验证了测距方案的正确性和实用性。在现场试验中，改进的阻抗测距法对短路故障的测距误差小于0.05km；基于模波速度差的单相接地故障测距方法在24组试验中有17组测距误差小于1km，基本满足现场要求。
Fault location technology on distribution line can quickly and accurately find the fault, which is conducive to timely repair the line and restore the safe and stable operation of the power system. However, Conditioned by the radial structure of the distribution network, short and multi-branch lines, overhead-cable transmission mode, and usually non-transposition structure, these features make it more difficult and tedious to find fault point than transmission network. As the distribution lines are too short to accept big error of fault distance, fault location in distribution lines requires high accuracy. Moreover, the single-phase-to-ground fault location in non-effectively grounded system is a long-standing question. Therefore to solve fault location problem on the distribution line has important theoretical value and practical value.Since the object of this paper is the non-effectively grounded distribution system, the fault is divided into short-circuit fault and phase-to-ground fault.For the short-circuit fault, the core problem is to improve the existing fault location methods to fit for the characteristics of distribution lines and achieve the high fault location accuracy. First it proposes the improved impedance measurement method which uses the distributed parameter model to improve the location accuracy; Then to achieve a comprehensive solution, it discusses combined fault location method which includes traveling wave fault location method and improved impedance measurement method. It also analyse the possibility of application of the traveling wave fault location method and gives consideration to the unique structure of the distribution lines.For the phase-to-ground fault, the core problem is to find a proper fault location method to fit for the characteristics of distribution lines and achieve the effective and high fault location accuracy. The paper makes some improvement on the fault location method based on the gap of traveling wave propagation time: gives the access to get the aerial mode and zero-mode traveling wave; proposes the way to distinguish the first wave by the modulus maxima with some steepness; proposes fitting methods to the zero-mode wave velocity by the singularity index and kurtosis; as an auxiliary supplement adds the fault location method based on the relative value of the damped frequency band.The paper also takes the distributed generation into account, discusses the application of the fault location algorithms proposed, and adds double-terminal traveling wave fault location method when the system of distributed generation is strong.The paper accomplishes the complete fault location method on the DLFLS-01(Distribution Line Fault Location System). Simulation tests, tests based on traveling wave test platform, and field tests verify the feasibility of fault location method comprehensively. The fault location method on the distribution network has more accuracy and a wider applied range. In the field tests, the errors of improved impedance measurement method for short-circuit faults are less than 0.05km; among the 24 single-phase-to-ground faults, there are 17 groups, of which the errors of fault location based on the gap of traveling wave propagation time and the relative value of the damped frequency band are less than 1km.
