An Intelligent Optimization Method Of Power System Stabilizer Parameters

For the purpose of guaranteeing the economical operation of power system, theinterconnection of regional power networks becomes a trend and requirement in thedevelopment of modern power system. With the enlargement of network and increase of thetransfer power, inter-area low-frequency oscillation has been a serious bottleneck of powertransfer across interconnecting power system. Power system stabilizers (PSS) has theadvantages of clear physical concept, simple electric circuit and debugging conveniently,becoming an effective measurement of damping low-frequency oscillations. In order toensure PSS operating safely and reliably, field trials should be done before PSS applying toverify the parameters.Nowadays, the parameters of PSS obtaining from field trials that rely on theexperience of experimenters have some blindness. According to the provision of excitationsystem and PSS from STATE GRID, combining the real situation of power system, aparameters optimization model of PSS is established in this paper while an intelligentoptimization method is sought for, which can be widely used to solve this question, getrobust PSS, and satisfy the operation requests of power system comfortably.Related basic theory of PSS is introduced in this paper firstly, mainly including itsmechanism of damping low-frequency oscillations, PSS’s characteristic of different inputsignals and its application in power system. Then, in the interest of the measurementdifficulty of uncompensated phase-frequency characteristics in some units’ excitationsystem presently and the actuality that the measurement only work under one operatingcondition, a new method based on equivalent excitation system of grid to computeuncompensated phase-frequency characteristics is introduced, which obtains equal gridoperating conditions via field trials data, and then obtaining the excitation systems’uncompensated phase-frequency characteristics. Based on above, a method to optimizeparameters of PSS is discussed, which can establishes corresponding optimization modelsand solves the question through particle swarm optimization algorithm according todifferent input signals. The correctness and applicability of the method is verified by an example analysis.The intelligent optimization method of PSS parameters has been effectively applied inthe soft package named “Network and Excitation System Model Equivalent based on fieldtrial data&Checking Parameters Automatically Method in Time-Domain”, and also hasbeen used in the technology reform project from CENTER CHINAGRID 《Field MeasuredParameters and Model Combing of Important Unit Excitation Systems&OptimizationParameters of PSS in CENTER CHINA GRID》.