【作者】 张晓；

【导师】 高金峰；

【作者基本信息】 郑州大学 ， 电工理论与新技术， 2005， 硕士

【摘要】 本论文以通用分岔分析软件AUTO97为工具,应用分岔理论及数值仿真方法,对电力系统电压稳定性问题进行了研究。主要开展了如下几方面的工作:分析和总结了电力系统主要元件特性对电压稳定性的影响;三种典型电力系统负荷模型对电压稳定性的影响;发电机模型对同一典型电力系统模型的电压稳定性的影响等。通过研究,本文取得了一些具有理论与实际意义的结论,主要结果总结如下: 一、电力系统主要元件特性对电压稳定性的影响 电力系统的强非线性和各种元件的动态特性是引起电力系统电压稳定性问题的根源。本文在目前有关电压稳定性研究成果的基础上,对电力系统主要元件如负荷、有载调压变压器(OLTC)、发电机和静止无功补偿器(SVC)的特性对系统电压稳定性的影响进行了分析和综述。 二、负荷模型对电压稳定性的影响 本文研究了一般静态综合负荷模型、GNLD综合负荷模型以及WALVE综合负荷模型对电压稳定性的影响: 1.就电压稳定性而言,恒功率型较恒电流型更易失去稳定性,而一般恒阻抗型负荷不存在电压稳定性问题。 2.对于温控型负荷或恒温性负荷较重的地区必须采用更接近实际的负荷模型如GNLD综合负荷模型,它的功率恢复特性将对电力系统电压稳定性产生较大影响。 3.WALVE综合负荷模型的电压稳定性问题比一般静态综合负荷模型复杂的多,采用WALVE综合负荷模型的电力系统还存在Hopf分岔的情况。因此,要深入研究电压稳定性的本质,必须采用更切合实际的动态负荷模型。 三、发电机模型对电压稳定性的影响更多还原

【Abstract】 In this thesis, studies are made on the problem of voltage stability in power system based on bifurcation theory and numeric simulation method using AUTO97, a general continuation and bifurcation software. The questions addressed in this work are: analyzing and summarizing the effects of main component characteristics on voltage stability; the effects of three typical load models on voltage stability; the effects of generator models on the voltage stability of a typical power system and so on. The main body of this thesis consists of the items as follows:( Ⅰ ) The effects of main component characteristics on voltage stabilityThe strong nonlinearity of power system and components’ dynamic characteristics are the source leading to voltage instability. Based on the present achievements, this dissertation discusses and summarizes the effects of main component characteristics such as load models, OLTC, generator models and SVC on voltage stability.(Ⅱ) The effects of load models on voltage stabilityThe main analysis objects in this thesis are generic static load model, GNLD integrated load model and WALVE integrated load model. The analysis results as follows:1. The characteristic of constant current type load is more favorable for voltage stability than constant power type load. The characteristic of constant impedance type load doesn’t affect the voltage stability.2. In the areas where there are more constant temperature type loads or loads controlled by temperature, the realistic loads models such as GNLD integrated load model should be adopted, because the voltage stability is more influenced by their power comeback characteristic.3. As far as the voltage stability is concerned, the WALVE integrated loadmodel is more complex than the generic static load model because of the existence of Hopf bifurcation in the power system. Therefore, the more realistic dynamic load models must be adopted in studying the mechanism of voltage stability.(Ill) The effects of generator models on voltage stabilityThe study is made on a typical power system. The analysis results as follows:1. If the generator model employed is four order or six order model which thinks of g winding, the system will undergo supercritical Hopf bifurcation; if the generator model employed is 3 order or 5 order model which doesn’t think of g winding, the system will undergo subcritical Hopf bifurcation. No matter what characteristic of the Hopf bifurcation the system undergoes, it will appear voltage oscillation and lose its stability gradually via period doubling bifurcation leading to chaos or torus bifurcation leading to torus cracking.2. The analysis result is more optimistic when the generator model employed is five order or six order which thinks of the subtransient of the generator than three order or four order which only thinks of the transient of the generator. Then, the dynamic stability range of the system will be increased accordingly.3. It isn’t appropriate to employ the two order generator model in the dynamic voltage stability analysis because it approximatively thinks of the excitation system and the result isn’t precise.更多还原