【作者】 杨雄平；

【导师】 段献忠； 石东源；

【作者基本信息】 华中科技大学 ， 电力系统及其自动化， 2007， 博士

【摘要】 复杂、多变的电网拓扑结构及运行方式,给电力系统带来了许多新的问题及安全运行隐患。分析和利用电网拓扑结构、研究不同运行方式及电网拓扑结构变化组合,对于电力系统分析计算及电网安全运行具有重要的意义。本文致力于电力系统网络拓扑结构分析及运行方式组合方法的研究。研究成果已成功应用于多家省、区域电网继电保护整定计算系统,有效提高了整定计算的效率及保护定值的准确性,确保了保护装置在各种可能运行方式下的动作可靠性。提出了一种利用电力系统物理网络拓扑分析其几何网络拓扑结构特点的新思路。基于节点阻抗矩阵元素能够反映在系统全局范围内节点间所有电气耦合的特性,利用其蕴含的物理网络拓扑连接关系,引入了两个简单的数学等式判据,得出了一种新颖的辨识割支路和割节点的物理拓扑分析算法。相对于传统的几何拓扑分析算法,文中提出的辨识算法简单、直观,具有明确的物理意义。针对现代电网具有的交错嵌套、纷繁复杂的环网结构特征,分析了对保护定值影响较大的典型环网拓扑结构变化,借助于局部节点及其阻抗矩阵元素构成的等值网络所反映的电气耦合物理意义,提出了一种基于环网电气耦合分析的运行方式组合方法。该方法定义了两个环网电气耦合指标,能够有选择性、快速准确地确定对保护定值影响较大的环网开断线路。分析了高压电网整定计算中所关心的厂站拓扑结构及运行方式变化特点,提出将其内部元件方式的变化看作为一个整体单元的参数切换,根据整定计算所需要的故障计算量,引入了两类厂站方式灵敏系数。通过预先确定对故障电流和配合系数影响较大的厂站及其方式,能够有选择性地考虑厂站方式变化对保护定值的影响,从而有效减少了不必要的组合方式及故障计算。为了适应运行方式组合带来的网络拓扑结构变化,采用基于节点阻抗矩阵的故障计算数学模型,通过预先形成不同方式下的厂站单点或两点Π型等值网络参数,将厂站方式的切换转变为等效的简单网络操作。同时,对支路追加的顺序和故障计算相关涉及节点的修改次数进行了优化,提出了一种分层降阶的涉及节点阻抗矩阵修改方式,有效减少了涉及节点阻抗矩阵元素修改的次数,大大提高了计及运行方式组合的故障计算速度。提出了一种母线综合阻抗计算时的网络拓扑分析算法。该算法结合了物理网络拓扑和几何网络拓扑分析,通过电气物理路径判断,剔除了无效的几何路径搜索方向,保证搜索方向始终指向系统侧,从而有效避免了辐射分岔支路的深度搜索以及回溯的复杂性。研究了现代电网复杂环网拓扑结构所带来的整定计算断点求取问题。根据环状网络解开为无环辐射网络分析,得出了基于网络拓扑节点度数的快速解环方法。在此基础上提出了一种适合于反时限方向过流保护整定计算的断点求取算法。随后,结合国内阶段式定时限方向保护整定计算普遍采用逐段整定及配合原则的特点,对其中的配合死锁环网及其断点进行了分析讨论,并同反时限方向过流保护进行了比较。通过预整定形成死锁环网,提出了一种用于定时限方向保护整定计算的断点计算算法。更多还原

【Abstract】 Complicated operation mode and changeful power network topology brings some hidden trouble to power system’s safety. It is very significative to analyze and make use of the network topology, and to study the combination of different operation modes and power network topology configurations, for power system analysis and safe operation. This dissertation devotes to the study of operation modes’combination and network topology analysis. The research productions have been applied in the relay coordination softwares for many provincial and regional power networks. And they improve the veracity of setting, the efficiency of relay coordination software and the reliability of relay equipments’action.Firstly, this paper exploits a novel physical topology analysis method to analyze the characteristic of corresponding geometrical topology. The elements of impedance matrix (Z-matrix) can concentratedly reflect all the electrical coupling of different buses in the systematic scale. Recurring to the global topological attributes concealed in Z-matrix, a new physical topology analysis algorithm to identify cut edges and vertices is presented, it introduces two simple equality criterions derived from the reduced Z-matrix elements. This novel algorithm adequately utilizes the physical topological properties concealed in the Z-matrix of power system. The improvement over existing graph-theoretical approaches is in that this new algorithm has more direct-viewing, simplicity, specific and important physical significance, which can borrow ideas to insight and research the topology configuration in power network.Secondly, based on the electrical coupling paths described by physical parameters of equivalent network derived from the reduced impedance matrix, this paper analyzes the representative dynamic change of mesh network topology which has an influence on the calculation of setting, a new method in combination of operation mode is presented. It introduced electric coupling of loops which cake care of the influence of mesh network selectively based on two criterions.Furthermore, according to the topology characteristic of power substations or plants considered in relay coordination, the operation mode change of elopements in the power substations or plants can be thought as a whole unit with different impedance parameters. Two types of sensitivity factors are derived that demonstrate the relationship between the fault current or coordination coefficients and different operation modes of different substations or plants. The operation mode of substations or plants which have great impact on the setting of relays will be taken into account selectivity in the relay coordination. The speed of fault calculation for relay coordination will decrease remarkably when considering varying of operation conditions including the switching of operation conditions of substations or plants and line outages simultaneously. Two methods are presented to improve the arithmetic of fault calculation based on the impedance matrix: 1) the substations and plants in various operation conditions are reduced into a single-bus or two-bus equivalence networks in advance, the switching of which are substituted by the change of the equivalence networks; 2) the elements of the partial impedance matrix for fault calculation are classified, the number of the elements need to be modified decreases gradually according to their necessary and the optimum sequence of modification. These improved methods decrease the modification of the impedance matrix and quicken the speed of fault calculation remarkably.Next, a new algorithm of network topology analysis for equivalent impedance calculation is presented. This proposed algorithm combines the physical topology and geometrical topology. Ineffective directions of geometrical path search are excluded through the judgment of electric physical paths, which ensure the search direct to the power system all along, and the complex back-tracing and the depth search of radial branches are avoided.Finally, this paper studies the determination of minimum break point set (MBPS) owning the intersectant and complicated meshed power network. Based on the of mesh network being transformed into radiate network theoretic analysis, the fastest loop opening analysis criterion principle is obtained. And an algorithm to determine MBPS for inverse-time directional overcurrent relay setting coordination grounded on analysis of opening loop is brought forward. The definition of coordination deadlock meshnetwork is analyzed according to the property of relay coordination of definite-time relays in power systems, and this paper discusses the difference between the break point set in the definite-time relay coordination and inverse-time relay coordination. By obtaining the coordination deadlock meshnetwork loop through pre-coordination, the paper improves the functional dependency methodology and proposes a new method to determine the minimal breakpoint set which is used to break the obtained deadlock loop.更多还原