A Clustering Method For Coherent Generator Groups In Dynamic Equivalents Of Power System

Dynamic equivalents are used to reduce the computing effort and manifest the principal characteristics of power systems. In general it consists of coherency method, mode method and identification method so far. The coherency method is widely used for its advantages in physical transparence, adaptation to no-linear systems and big disturbances, and it can be used directly in transient stability analysis. It is also fit for equivalent of large-scale system with a great velocity and a controllability of precision. One obstacle is the division of the coherent generator groups. Here a clustering method is introduced. The main work of this thesis is as following:1 The relevant documents of dynamic equivalent in recent years, especially the coherency method, are studied, accompanied with the principals, the actual algorithms and the computer programs of the method. In this dissertation, different methods of equivalents are compared by showing the advantage and the disadvantage of each one.2 The relative associated model is introduced and later, the conception of relative associated model of power system. The consecutive steps for calculating the relative associated gain matrix of power system are inducted. The case studies of a 36-bus system show the significance of the matrix. Finally, different clustering methods are presented.3 The conception of mechanical and electrical distance of power system is induced which can be served as an index of the association degree between any two machines when taking both aspects, the mechanical and electrical ones, into account. The external system can be divided into several parts, the number of which depends on the result obtained by...