【作者】 王波；

【导师】 曹一家； 江全元；

【作者基本信息】 浙江大学 ， 电力系统及其自动化， 2010， 硕士

【摘要】 高压输电线路故障定位研究如何及时、准确地找到故障位置,从而不仅能快速修复线路,发现绝缘隐患和保证供电可靠,而且对保证整个电力系统的安全稳定和经济运行都有十分重要的作用。随着自动化技术的发展、信息传输技术的不断进步,尤其是近年来广域测量系统(Wide Area Measurement System,WAMS)的诞生与普及,为故障定位算法的研究带来了新的契机,因此基于广域测量系统的故障定位研究具有非常重要的现实意义和工程价值。在这样的工程背景下,本文对目前该领域中存在的问题进行了分析,并开展了深入的研究,取得了一些创新性的研究成果。首先,本文分析了WAMS给高压输电线路故障定位研究带来的契机。在简介WAMS系统的基础上,总结了现有基于同步相量技术的各种故障定位算法,按采集的数据量对各种方法进行了分类比较,并对其特点及应用效果作出评价:进而分析了当前该领域的研究热点,并指出了故障定位理论还需要进一步研究和突破的地方,引出了本文的研究内容。其次,为提高WAMS感知电网拓扑改变的能力,从而给输电网络的故障定位研究提供精确的拓扑信息,本文提出了母线有功负荷相对改变量指标用于判断母线负荷是否发生负荷构成改变,并基于此发展了一种新的电力网络拓扑实时分析方法。该方法依靠同步相量测量单元(Phasor Measurement Unit,PMU)测量量突变检测和潮流分析进行初步判别;对于拓扑改变后线路两端潮流仍处于合理范围内的特殊情况,则依靠假设验证法进一步进行区分和定位。仿真实验表明该方法能够有效地区分拓扑改变与大负荷增减扰动。第三,针对特定电网结构的故障定位问题进行了深入的研究,本章提出两种基于PMU的实用故障定位算法。首先,针对分支线路为长距离线路的情况,提出一种基于多端PMU的输电线路故障定位算法,假定线路各端点均配置PMU,利用新定义的节点电流非平衡量指标,发掘其本身的内在特性,把故障支路判断和精确定位融为一体,从而实现快速、准确的故障定位。其次,针对分支线路为较短接入线路的情况,提出一种基于双端PMU的多分支输电线路故障定位算法,仅假定线路两端配置PMU,通过多次的故障区域判断,锁定故障发生所在支路,以最少的PMU实现精确故障定位,从而解决双端故障定位算法的通用性问题。仿真实验表明上述两种方法能有效地解决多分支输电线路的故障定位问题。第四,为实现故障定位算法在实际大电网中的应用,本文提出两种适于任意电网结构的实用故障定位算法。方法1首先根据对称分量法和线性叠加原理,建立故障后的附加正序网络并定义了故障定位因子;进而应用波形匹配原理,对故障时的定位因子与仿真波形进行匹配,以决定故障发生的位置;在方法一的基础上,方法2推导出关于电网故障位置的一元目标函数,即转化为最小值求解问题,进而基于该函数运用遍历搜索方法寻找故障点的位置;上述两种算法仅利用电压相量进行计算,能够避免由电流互感器饱和所带来的误差影响,且仅需少量PMU的配置。仿真实验表明该方法能够有效地定位任意电网结构的短路故障,并且不受故障类型、过渡电阻等因素的影响。最后,总结了本文二至四章所提出的基于WAMS的各种故障定位算法,分析评价了本文各项研究的创新点和不足之处;展望了未来的进一步研究方向。更多还原

【Abstract】 Fault location algorithm for High voltage transmission lines can promptly and accurately detect the fault point. It not only can greatly decrease the restoring work and outage time, bus also can detect the defective insulation. Fault location plays an important role in the security, stabilization and economic operation of power system. With the development of automation and information transfer techniques, WAMS (Wide Area Measurement System) comes into being which brings new opportunities for the Fault Location research. As a result, there is a great practical significance and engineering value in the Fault Location research based on WAMS. Under such engineering background, this thesis conducts research on this research interests and obtains some innovative research results.Firstly, the new opportunities for the research on fault location based on WAMS are analyzed. After the basic principle of WAMS is briefly introduced, the various existing algorithms based on synchronization technologyis are concluded. These different methods are classified and analysed by the amount of data used, while their characteristics and application performance are evaluated. At last, the current research interests in this area is presented, and the existing problem on the fault locagtion theory is pointed out, which leads to the research content of this thesis.Secondly, in order to obtain the accurate topology information for fault location research and improve the ability of perceiving the power network topology change based on WAMS, a new index, the relative variation of bus load, is proposed to identify the change of load structure. On the basis of this new index, a novel real time topology processing method is proposed. Most of the topology change perturbations can be identified by measurement change detection and power flow analysis. But for the special case that the power flow change is within the reasonable range after the perturbation, the hypothesis-verification method is used to distinguish topology change from large load change. The simulation results show that by using this algorithm we can effectively locate the topology change.Thirdly, the particular power structure in transmission network is studied in this chapter, and two kinds of practical PMU-based fault algorithm are proposed. In algorithm one, the branch lines are assumed as the long-distance lines, and then an efficient PMU-based fault location technique for the multi-terminal transmission lines is presentd. It is assumed that all the terminals are placed with PMU. This technique is based on a fault location index, which is defined as nodal current unbalance. By analyzing the special features of the index, through fault section identification and exact fault location, the fault point can be accurately and effectively achieved. In algorithm two, the branch lines are assumed as the short-distance lines, and then an adaptive PMU-based fault location technique for transmission line with tapped lines is presented. It is assumed that only two terminals are placed with PMU. Through multi fault region estimation, the fault line section can be located. Then the two-terminal fault location algorithm can be applied to implement high accurate fault location. This method solves the problem with the minimum of PMU, which also give a generic algorithm for the two-terminal transmission line.Fourthly, in order to achieve practical application of the fault location algorithm in power grid, two kinds of fault location algorithm suitable for transmission network with any construction are presented in this chapter. In algorithm one, basing on symmetrical component method and linear superposition principle, the additional positive sequence network is established. Then the fault location factor is defined and matching during-fault recorded factors with the during-fault simulated factors is used to determine the fault location. In algorithm two, a fault location optimization model is derived. Using the objective function, the line-based search method is applied to search all lines in the suspicious fault regions and find the exact fault point where the matching degree index is minimal. Numerical studies verify that the two proposed fault location method can accurately and quickly locate a fault under the conditions of different fault types, fault positions, and fault resistances. The proposed approach is especially promising for large-scale power system, and only requires sparse PMU placment.Finally, the researches in this thesis are summarized, and the innovation points and inadequacies are analyzed and evaluated. Then the further work is prospected.更多还原