Research On Small Signal Stability And Control Method For Power System With Large Scale Wind Power

In order to alleviate the problems of energy shortage and environmental pollution,renewable energy has developed rapidly in the world due to its advantages of clean and pollution-free.However,wind power and other new energy sources are affected by natural factors,which have the uncertainty of randomness and fluctuation.At the same time,with the increasing demand for power grid load and the pursuit of benefits by power enterprises,low frequency oscillation caused by weak damping mode has become an important factor restricting the safe and stable operation of power system.Therefore,considering the uncertainty of wind power,this paper studies the influence of wind power access on the small disturbance stability of power system and its control method,which has important theoretical significance and research value for ensuring the safe and reliable operation of power system after the wind turbine is connected to the grid.In this paper,based on the dynamic model of doubly fed induction generator(DFIG).Firstly,the stochastic response surface method(SRSM) and Nataf transform are used to analyze the influence of wind speed correlation on the small disturbance stability of power system.At the same time,probability distribution point selection method based on linear independent principle is used to choose the effective distribution point,which improves the computational efficiency of SRSM.Secondly,the risk assessment index of small disturbance instability is established to evaluate the risk of small disturbance probability instability,while an active-power adjustment strategy proposed to reduce the risk of small disturbance instability.The adjustment strategy is based on the objective function considering the active-power rescheduling cost and the power adjustment is at the minimum while the instability risk index of small disturbance is smallest.Moreover,by taking the sensitivity of damping ratio into account,an improved algorithm based on NSGA-? is proposed to solve the issue.It effectively reduces the disturbance caused by the active power adjustment of the system,and improves the stability and speed of the system operation.Finally,an DFIG control method based on the Passivity-based control and Active Disturbance Rejection Control(ADRC) is proposed.It improves the small disturbance stability of power system.In the 10 machine 39 bus system,the effectiveness of the proposed model and control scheme in this paper is verified.