Research And Application Of Self Shunt Static Excitation System

As the basic control unit of electric po wer system,static excitation system is essential to the reliability and stability electric generators.Improving the controlling function of this system is considered as one the most economic and efficient measures to stabilize the electric po wer system.In C hina,the expectations on static excitation systems of synchronous generators are rising as its electric control system is developing rapidly;introducing static microprocessors into excitation systems fulfills this requirement of the development.Self-shunt static excitation systems,of which the structure is simple and maintenance is easy,is being increasingly adop ted in C hina.Through setting calculations of the key parameters of static excitation system,which includes the design,conformation and subassemblies,of machines #1,#2 and #3 in Tianjin Cheng Nan gas power plant,this paper studies the hardware composition as well as the control software design of d igital static excitation systems.This paper also draws up principles of setting calculations in every link of the system(excitation transformer,magnetic field breaker,silicon controlled rectifier,nonlinear resistance device,overvoltage protection de vice of the rotor,system loss etc.)and provides detailed data calculated according to these principles.Based on the parameters presented in this paper,the static excitation systems of machines #1,#2 and #3 in C heng Nan power plant are experimented when adjusting and connecting to the grid.The results recorded include initial excitation manually and automatically,raising voltage from zero,step response,de-excitation as well as PSS examinations after co nnected to the grid.Data collected from the experiments are described in detail as well as shown on waveform graphs.The outcomes prove the contribution of the theoretic in this paper to optimizing setting up the parameters of static excitation systems and enhancing the stability of the whole generator set in operation.On this basis,the paper discusses and analyses the superiority of self-shunt static excitation systems as well as the problems in its design,selection and application.