Modeling And Analysis Of Power System By NETOMAC

Deregulation is the inevitable trend of the electric power industry. In China,deregulation is only in a starting stage,therefore,it is necessary and urgent to research a series of technology and theories about electricity markets,especially tecknology and theories on pre-dispatch schedule,the kernel of electricity markets.Excitation systems can impose significant effects on the stability of power systems. Although performance indexes of excitation systems are stated in all kinds of standards,there isn't a parameter setting method for excitation systems in order that their performance indexes can meet the requirements in the standards.Although eigenvalue method is the traditional method for power system small signal stability analysis,its application is limited by the problem of large quantities of computation when analyzing bulk power systems. Frequency domain method,however,takes an advantage in the aspect.Based on NETOMAC,a software package for power system simulation,the model and algorithm of pre-dispatch schedule in generation markets,excitation system parameter setting,and power system small signal stability anaylsis are studied in this thesis. The main work is as follows:A model of pre-dispatch schedule is proposed,whose target is to minimize the market purchasing price (MPP) in the whole pre-dispatch period. Then according to the characteristics of pre-dispatch schedule,the model of pre-dispatch schedule is simplified to minimize the MPP in each pre-dispatch time,and a three-step algorithm of pre-dispatch schedule is designed:Dealing with the optimal problem in the whole period of pre-dispatch with static planning method,Solving the problem of combination of machines with PR1 method,resolving problem of optimal power flow (OPF) with modified Powell method. (2) A new method of parameter setting for excitation systems is proposed. Firstly,the large signal performance simulation test of the excitation system is conducted and the objective response of the excitation system is described with its large signal performance indexes,and then the parameters of the excitation system are identified. Secondly,the small signal performance simulation test of the excitation system is done and the parameters of the excitation system are optimized by the 1TAE rule in order to enhance the small signal regulation performance. IEEE AC1,AC2,and ST1 excitation systems are selected as examples,and their parametersare identified and optimized in order that the performance indexes of the excitation systems can meet the requirements of the standards.(3) A method based on some test signal (Test Signal Method) is developed to find the dominant oscillating frequencies and dampings associated with any generator in the system. The method can be realized easily by time domain simulation using electromechanical transient programs. The theoretical background of the test signal method is the theory of mechanical admittance and mode identification,which is based on the frequency scanning of the test signal and has already been used widely in mechanical engineering. The study cases show that the test signal method developed in this paper can be effectively applied in small signal stability analysis and PSS design.