Probabilistic Small Signal Stability Analysis And Control Of Power System With Wind Power And Photovoltaic Power

With the wind power and photovoltaic power penetration continues to improve,the random effect on power system stability is gradually deepened.The small signal stability and low frequency oscillation suppression is one of the most important problems.Traditional deterministic small signal analysis and control methods,which do not consider the uncertainties scene,cause results to be inaccurate.To address the above problems,this paper will consider the correlations and uncertainty caused by wind power and photovoltaic power,then study the probabilistic small signal stability analysis and low frequency oscillation suppression for power system with wind power and photovoltaic power integration.The main work is as follows.Firstly,the dynamic model of wind farm and photovoltaic power generation is established,which is suitable for small signal stability analysis.Considering the random variation of wind and solar radiation,the dynamic model of doubly fed wind turbine,including mechanical system and doubly fed induction generator,and electromechanical transient model of photovoltaic generation system,including photovoltaic array and inverter are established.Then the wind power and photovoltaic model are connected to the power system simulation toolbox(power system simulation,PSST),and the mathematical model of the small signal analysis of the power system with wind and photovoltaic power is established.Then,a PSSSA method based on discrete point estimation method is proposed in this paper considering the correlation of wind speed and solar radiation.At the same time,the Gram-Charlier expansion algorithm is introduced to fit the cumulative distribution curve of the output random variables.The effectiveness of the proposed algorithm is verified by comparing the results with Monte Carlo method.Finally,in order to improve the dynamic stability of power system with wind power and photovoltaic power integration,a static var compensator based on supplementary damping controller is introduced into the system.Because the goal representation heuristic dynamic programming has strong learning ability and adaptability to the change of the running state of the system,this paper introduces the design of GrHDP-SDC,and compared the control effect of PSS-SDC and GrHDP-SDC under different operation mode.The results show that GrHDP-SDC can improve the dynamic performance of the system better,and it is more suitable for the system with changeable running state.