The Research Of Power System Stability In Excitation Control System

Modern life couldn't leave from electricity,therefore,the problems of power system's stability deserve our great energy concentrated on.And the first problem supposed to be solved in power system is low-frequency oscillation.There are two solutions of solving the problem of low-frequency oscillation,including first system strategy and second system strategy.According to the international conference of great electricity net,PSS included in second system strategy is the preferred.The paper based on the reformation by the school of precision instrument in Tianjin university for professional master's education,is a outcome by a cooperation education with the company HNAC.The plan of education is targeted made by taking advantage of the school scientific research and the company's practice convenient,combining the company's industrial upgrading and the problem urgent to be solved.The research comes from the company's reality need,mostly completed in the company.For the design of excitation regulation PWL4 C problem,it complete the model of PSS2 B and solve the excitation regulation's anti-regulation problem,applying in the Laoantong hydropower station,getting a great result.The The main work of the paper:1.The function and structure of excitation system are analyzed firstly,and then classify the problems of power system stability.Finally a strategy to solve the low-frequency oscillation proposed by gain a extra positive damping.According to the example of low-frequency oscillation all over the world,it is verified to assemble the PSS.And though the analyzes and comparisons from PSS1 A to PSS4 B,we select the best solution,PSS2 B.2.The principle of low-frequency oscillation are analyzed,and from the Model of Heffron-Philips deduced the model of excitation system.Moreover,analyze the restrain of low-frequency oscillation from damping torque and synchronizing torque,and then come up with a parameters settings way of PSS though phase compensation.3.Though HNAC company putting out a Excitation regulator PWL4 C,select the model of PSS2 B to complete the PSS function and design the software and hardware of the regulator.Besides,though bilinear transformation method and the differential method the PSS signal are discretization.Finally get the signal of frequency of generator though the way of software.4.From the perspective of industry field,compete the PSS field experiment and get the curve of the respond.The experiment include:Voltage of the machine stepexperiment,PSS critical gain experiment,anti-regulation experiment.