The Analysis And Research Of The Abnormal Phenomenon Of PSS For Nanpu Unit In Fujian Power Grid

Power system stabilizer (PSS) is a kind of additional excitation control device, practice shows that the unit which installed with power system stabilizer is the most economic and effective measures for suppressing low-frequency oscillation and improving the dynamic stability of power system. Some practical experiences have been calculated during the test and operation of PSS of every unit in Fujian Province in recent years, most of the application of PSS played a positive role in improving dynamic stability of power systems in our province. With the deep usage of PSS, the abnormal phenomenon of fluctuations increased of active power has appeared in few units when the PSS has been put into operation at certain times. It has a large engineering practical significance to do the research which aimed at finding the reasons and resolve the problem of the abnormal phenomenon.This thesis introduced the theory, concept and analysis method of low-frequency oscillation of power system, analyzed the operating principle of the PSS restrains low-frequency oscillation and commonly used PSS models, especially performed a minute analysis of 2A PSS model and parameters of Nanpu unit; this thesis used the method of field test to check rise and fall of power of No.2 unit of Nanpu unit from four aspects of system oscillating source, soft hardware of excitation system, AVR and PSS parameters, interaction of governor and PSS, which has defined the reason of power rise and fall of No.2 unit is that the abnormal phenomenon output of No.2 unit. At the same time, the test has provided data support for theory analysis. Meanwhile, this thesis mainly introduced the advantages, algorithm, parameter settings of analysis method of Prony digital signal, then studied spectrum analysis and oscillation research of recorded wave curve and date of field using Prony analysis method, and try to explore the reason of the abnormal rise and fall of power. According to the measured model parameters of all the dynamic components of Nanpu power plant, the author founded excitation system of Nanpu unit, governor system, PSS and generator model in the environment of Matlab/Simulink simulation. On this basis, the thsis comprehensively studied the influence of different PSS parameters on the active power of generator unit, and compared the difference between the simulation results and actual recorded wave curve, at the same time, it studied the influence of PSS hardware part on the abnormal output of the power of unit, and analyzed whether there existed fault in the PSS hardware link.This thesis studied the abnormal phenomenon of PSS which appears for the first time for Nanpu unit in Fujian power grid using field test investigation, prony analysis of data and Matlab simulation confirmation which aimed to put forward theory explanation for appearance of the abnormal phenomenon, at the same time, resolved the abnormal phenomenon effectively through the measure of adjusting PSS parameters, replacing board which has better antijamming capability, and so on, which provided reference for the same kind of unit when they appears PSS abnormal phenomenon in the future.