在考虑各种动态环节的基础上，研究了并联电容器补偿对电力系统阻尼特性的影响。首先利用Heffron-Phillips模型，从理论上对该问题进行了详细的分析，解释了以往仿真研究中发现的负阻尼现象，并对其出现的规律进行了深入的分析和讨论。进一步利用一个10母线系统和新英格兰10要，39母线系统对理论分析的结果进行了验证。研究结果对提高电力系统小扰动稳定性具有一定的指导意义。

After some damaging blackouts, voltage stability and collapse have become worldwide concerned problems. In this paper, we focus on the aspect of voltage stability. An improved voltage stability index named LI is presented, which can give an accurate indication to power system voltage instability with considering the influence of the load model. Its calculating speed is very fast, so it can be used in the on-line monitoring and control of power system voltage stability. An appropriate external equivalent method is also presented to speed-up the calculation. So index-LI can be used in regional operating centers of the interconnection power systems. As an application of index-LI, approaches to identify voltage stability weak buses, coherent generator set and coherent load set of a weak bus are given in the end. New-England system and IEEE 50-generator-145-bus system are used to illustrate the accurateness and effectiveness of our methods.

对电力系统小扰动稳定域的微分拓扑学性质进行了初步探讨。首先，简单回顾了小扰动稳定域的相关定义、边界组成及其性质；然后，给出一种基于优化过程实现对小扰动稳定域Hopf分岔界面追踪的算法；最后，利用一个简单的3节点系统，示例了小扰动稳定域边界面非凸和内部存在封闭不稳定（空洞）区域的现象，并对小扰动稳定域内部空洞区域随系统参数变化的规律进行了研究。该工作对于进一步深化对电力系统小扰动稳定域微分拓扑学性质的研究具有一定帮助。

对所发现的小扰动稳定域内部存在空洞现象进行了机理分析，力图找到这一现象出现的原因。对分岔问题进行深入分析后，发现算例系统小扰动稳定域内部空洞现象的产生是由该系统的Hopf分岔退化现象导致的，而空洞区域的破裂和最后消失则与该系统不同Hopf分岔曲线的相交有关。该研究思路和研究方法，希望能对进一步探求真实电力系统小扰动稳定域的微分拓扑学性质起到一定的启示作用。

After some damaging blackouts, voltage stability and collapse have become worldwide concerned problems. In this paper, we focus on the aspect of voltage stability. An improved voltage stability index named LI is presented, which can give an accurate indication to power system voltage instability with considering the influence of the load model. Its calculating speed is very fast, so it can be used in the on-line monitoring and control of power system voltage stability. An appropriate external equivalent method is also presented to speed-up the calculation. So index-LI can be used in regional operating centers of the interconnection power systems. As an application of index-LI, approaches to identify voltage stability weak buses, coherent generator set and coherent load set of a weak bus are given in the end. New-England system and IEEE 50-generator-145-bus system are used to illustrate the accurateness and effectiveness of our methods.

In this paper routes to chaotic oscillation in power systems and relationships between chaos and various power system instability modes are deeply studied. Firstly, using a three-bus simple system, three routes may cause power systems to chaos are illustrated and discussed. They are route of cascading period doubling bifurcation (PDB), route of torus bifurcation (TB) and route of directly initiated by a large disturbance of energy. The route of cascading PDB is a typical route to chaos, where PDB is caused by a real Floquet multiplier (FM) moving counter to the real axis and going out of the unit circle from point (1, 0) in the complex plane. TB is caused by a couple of conjugate FMs going out of the unit circle with a nonzero imaginary part in the complex plane. Chaos caused by TB has some interesting features, such as self-organizing phenomenon, coexistence of divergent and chaotic subspaces, etc. The last route, which is directly initiated by a large disturbance of energy, is reported and studied for the first time so far as we know. Secondly, relationships between chaos and various instability modes are discussed. Also using a simple system, we illustrate the scenes that chaos leads power system to voltage collapse, angle divergence, or voltage collapse with angle divergence simultaneously when the stability conditions of the chaotic oscillation are broken. It tells us that chaos is very likely to be an intergrade existing in the transient stage after a large disturbance. In order to prevent the appearance of instability incidents effectively, it is necessary to keep up on the study of chaotic phenomena in power systems. All these studies are helpful to deeply understand the mechanism of various instability modes and to find effective anti-chaos strategies.

电力系统混沌现象与随机的往复振荡相似，在电力系统安全运行中是绝对不允许出现，的同时又由于混沌现象本身的复杂性，它的存在必然对电力系统稳定性研究和失稳预防等工作产生很大的影响。该文研究的重点是弄清楚混沌现象与系统不同失稳模式之间的关系和混沌现象在系统失稳发展过程中所处的实际位置。该文在研究过程中发现、并以示例分析了由于混沌极限环破裂(即混沌的稳定状态消失)而导致系统电压崩溃、角度失稳及电压和角度同时失稳的现象后两种现象，属于首次报道和首次研究。这些现象的存在表明，混沌现象可能是做为电力系统大扰动失稳过程的一个中间阶段而存在。

导致电力系统混沌出现的一种途径——环面分岔（TB, Torus Bifurcation）现象，属于一种较为复杂的动态分岔现 象，是由于一对复共轭弗罗奎特因子（FM, Floquet Multipliers）从其庞加莱截面（Poincaré section）上的单位圆同时穿出造成的。由环面分岔导致的混沌现象具有许多奇特的现象，如系统运动沿封闭环面分布、存在进一步的分岔与自组织现象以及有序与混沌共存等。该文利用非线性动力系统分岔理论和方法，针对一个简单的电力系统模型，对电力系统CTC现象的产生机理、表现形式和存在特点进行了详细的分析，所得结论有助于对电力系统混沌和各种失稳现象本质的理解。

天津电网在华北电网中属于受端，大量的电力需要长距离输送，加之天津经济发展较快，受用电量不断增长而电力走廊紧张等因素的影响，致使天津电网存在着电压失稳的威胁。借助连续潮流，模态分析和电压稳定指标等技术和分析手段。对天津电网的电压稳定性状态进行了深入的分析，指出了天津电网存在的问题和系统的薄弱环节，为天津电网更为安全稳定的运行提供了有益的信息。

电力系统中的混沌对传统的稳定分析和安全控制而言，是一个巨大的挑战+文中研究了发电机励磁顶值和PSS回路对电力系统的振荡失稳和混沌现象的影响。研究表明，当计及励磁顶值极限时，或在PSS参数配置合理情况下，可能导致系统Hopf分岔（HB）现象不出现或HB点与鞍-节分岔（SNB）点十分接近。由于在小扰动稳定框架下，HB出现是混沌产生的前提，HB不能出现时，混沌现象也将消失。合理配置PSS参数#可为系统提供正阻尼。从而能够显著抑制HB及混沌现象的产生。文中的研究也是作为找到有效抑制电力系统振荡失稳和混沌现象措施的一种有益尝试。