【作者】 张晋芳；

【导师】 王增平；

【作者基本信息】 华北电力大学 ， 电力系统及其自动化， 2012， 博士

【摘要】 利用电网多点信息的广域后备保护是解决当前电力系统中传统后备保护存在问题的有效途径。及时准确地掌握系统当前的运行方式和拓扑结构,可以为广域后备保护功能的实现奠定网架基础,而对故障元件的快速准确定位又是广域后备保护实现的关键功能。因此,论文针对网络拓扑快速分析以及故障元件定位两个方面内容展开深入全面的研究。以厂站内并行完成母线分析,并将结果上传主站完成厂站问拓扑分析的分层分布式拓扑建模方式从体系结构上保障了拓扑分析效率的提高。适应于基于WAMS的广域后备保护的需求,从应用于厂站内拓扑快速分析的矩阵方法以及PMU信息在拓扑分析中应用等角度对电力网络的快速识别问题展开研究。(1)仅利用开关状态量信息的厂站内拓扑矩阵型快速分析方法研究提出了一种基于虚拟阻抗的厂站内拓扑快速跟踪算法,通过赋给主接线中开关支路虚拟阻抗的途径,借鉴电网节点矩阵的形成及修改来实现对厂站内拓扑分析的初始形成及开关变位跟踪,实现了在已有拓扑结果上处理开关变位影响的效果,避免了传统矩阵法从初始邻接矩阵到全连通矩阵的重复运算。提出了一种基于开关连通路径的厂站内拓扑一体化分析方案,通过分析节点间开关连通路径与全联通矩阵中对应元素之间关系,利用主接线图形特征或邻接矩阵余子式形成两种路径发现算法,进而构建了以开关状态量为自变量的全连通矩阵函数,通过代入开关实时状态直接求值的方式实现了厂站内初始拓扑形成和开关变位跟踪的一体化分析。离线形成开关连通路径函数,在线加以实时跟踪的处理模式,从根本上提高了厂站内拓扑分析的效率。(2)网络拓扑分析中PMU提供的状态量和模拟量信息的具体应用研究提出了一套基于PMU信息混合运算的快速网络拓扑分析算法。其中,厂站内分析部分,在判断进出线母线归属的基础上,通过分析判断汇流母线节点关联注入电流是否满足KCL约束,实现划分连通片,进而完成厂站内拓扑分析任务；厂站间分析部分,在剖析网络树枝断开为电气岛追踪难点的基础上,利用广义KCL对区域网络的电流注入情况进行分析,并结合网络中树、连枝的动态划分,有效地解决了树枝断开追踪的难题。提出了一种基于最小二乘原理的厂站内开关拓扑错误辨识方案。首先对开关拓扑错误进行了分类,然后形成了联系开关状态量与线路及开关电流量的线性方程,并通过对电流相量实虚部同时分析的处理方式构建了对开关状态进行辨识的最小二乘算法,能够有效地处理各类开关拓扑错误。全网多点布置的PMU所提供信息的快速性和同步性对网络拓扑分析功能的实现产生了深刻影响,而由其保障的系统电气量计算的同时性也为实现广域后备保护关键功能——故障元件定位提供了有利条件。根据对故障点出现造成的电网拓扑结构破坏的不同处理方式,以及不同规模PMU测点信息的应用,论文侧重从电气拓扑一致性分析以及PMU量测布点有限的角度对故障定位方法进行研究。(1)提出了一种基于电气拓扑一致性分析的故障元件定位方案。通过分析支路故障和节点故障对网络结构破坏的不同影响,一方面利用是否满足电气拓扑一致性约束来快速定位支路故障,另一方面引入贝叶斯判别分析理论,综合利用故障前后电气量信息,以先验知识和后验概率相结合来实现对节点故障的准确可靠定位。(2)有限PMU布点提供电网局部量测信息下的全网故障定位方法研究。首先,通过对故障点在电网拓扑上加以等效消除,推导验证了电网故障前后节点矩阵的不变性特点。然后结合具有表达电网全局信息优势的节点阻抗矩阵,提出了两种分别基于近远区自适应搜索以及基于方差最小原理的故障定位算法,并能提供一定精度的故障点距离计算值。其中,前者在进行近远区故障定义和划分的基础上,利用PMU电压信息形成故障支路自适应搜索的策略,达到了近区故障定位效率高,远区故障搜索不遗漏的效果；后者通过分析节点等效注入虚拟故障电流数列的特点,利用方差最小原理实现第一步定位故障关联节点,第二步定位故障支路的目的,能够将搜索范围缩小到故障关联节点相连的支路集合中,有效地提高了故障定位的效率。更多还原

【Abstract】 The wide area backup protection is an effective technical way to solve the problems existing in traditional backup protection, in which the multi-point information from much wider area of power network could be used. The current operation mode and topology structure of power system need to be tracking rapidly and precisely, which could supply the wide area backup protection with the latest physical network grid information. Meanwhile, the fast and accurately location of faulted components is the key function for the implementation of wide area backup protection. Therefore, in the thesis the fast topology analysis and fault location will be the two attracting aspects needed researching fundamentally and comprehensively.The hierarchical and distributed topology modeling could improve the efficiency of topology analysis process in program architecture, in which all the substation configurations could be finished in a parallel way, and then the system network topology could be implemented based on the uploaded analysis results from different power stations and plants. Hence, in order to meet the requirement of wide area backup protection based on WAMS, the following fast topology identification contents, including novel matrix-based topology analysis method for substation configuration and the concrete application of PMU information in topology analysis, have been researched. The corresponding result of this part is as following:(1) Research on fast matrix-based substation configuration method only the circuit breaker status information in utilizationA new topology tracking algorithm is proposed based on virtual impedance. Firstly, the each switch branch in electric main connection is processed as one branch with virtual impedance; then, the original topology analysis and the tracking status change in circuit breakers in stations could be finished in a similar way as the formulation and modification of the nodal matrix for power network; finally, the aim to deal with the effect from status change of breakers on the pre-existing topology results could be achieved, and the repeat operation could be avoided which existing in the process from original adjacent matrix to completed connected matrix in traditional matrix-based method.In addition, a novel integrated topology analysis scheme is founded based on the breaker connected routes. In this scheme, the relationship between the breaker connected routes among two nodes and the corresponding elements in completed connected matrix is analyzed firstly. And two routes finding algorithms are proposed respectively according to the graphical characteristic of main connection or the cofactor signing simplification of adjacent matrix. Then the completed connected matrix in function way with the breaker statuses as variables could be established systematically, to which the integrated analysis for original topology formulation and tracking status change of breakers could be accomplished based on the finding of solution by substituting the real time statues of the corresponding breakers. Moreover, the topology analysis process, formulation of breaker connected routes function in off-line and the real time tracking in on-line, could enhance the efficiency of substation configuration.(2) Research on concrete application of state and analog information from PMU in network topology analysisA fast topology analysis algorithm is formulated based on the hybrid operation of PMU information. In the step of substation configuration, based on the bus grouping for inlet and outlet lines, how many connected pieces are grouped could be formed by judging whether the line currents incident to the concentrated bus node meet the KCL. Then the task of substation configuration could be finished. In the step of topology analysis among stations and power plants, the difficulty in islands analysis is pointed as the tracking the open of tree-branch firstly; then the generalized KCL is applied to the analysis for input currents of area network, and the tracking difficulty could be overcome combining with the dynamic grouping of tree-branches and cotree-branches.In addition, an identification method based on least square principle is established to correct the topology error in circuit breaker status. In this part, the types of switch topology error are determined at the beginning. Moreover, the linear equations are formulated in complex form to associate the switch status with the current in lines and breakers. After the partition of real and imag part for plural equations, the identification algorithm for switch status could be implemented by use of the least square method. The test examples have validated the efficiency of the proposed algorithm.The rapidity and synchronism of the PMU information from the multi-point in entire power network has affected the topology analysis function deeply. The calculation simultaneity of electrical quantities is also useful to the location of faulted components, which plays the key role in wide area backup protection. The occurrence of fault in power system will lead to the broken of power network topology. According to the different process modes and the variation in size of PMU measurements, the fault location methods have been focused in this thesis as following:(1) A fault location method is proposed based on the consistency analysis of electrical topology. The different between fault in branch and node have been analyzed in the broken for power network topology structure. As to the faulted branch location, the consistency for electrical topology is used to implement the rapid and accurate fault detection. As supplements, the Bayes Discriminant theory is introduced to finish the location of nodal fault precisely and reliably, in which the combination prior knowledge with posterior probability have been utilized about electrical quantities during the pre-and post-fault.(2) Research on fault location method for entire power network based on sparse PMU placementFirstly, the invariance characteristic of the nodal matrix for power network during pre-and post-fault is analyzed by the equivalent elimination of fault point. Secondly, having taken the advantage of the nodal impedance matrix, two fault location algorithms are proposed:one is based on the adaptive searching of near and remote sections, and the other is based on the minimum variance principle. The two mentioned algorithm could provide the fault point distance with a certain precise.In the former one, the classification of fault in near and remote section is defined. According to the nodal voltage information, the adaptive searching scheme for branches has been established. In this algorithm, the fault in near section could be located with high efficiency, and in remote section also can be determined without omittance. In the last one, the statistical characteristic of nodal equivalent input virtual fault current series has been extracted. Based on minimum variance principle, the first step to locate the suspected bus and second one to determine faulted branch could be finished. In this process, the searching scope could be limited to the branch set associated with suspected bus, from which the fault location could benefit more.更多还原