Research On Active Power Control Strategy Of Wind Farm Considering Wind Turbine Fatigue Load

In recent years,renewable energy has been favored by countries around the world.Among them,wind energy is playing an increasingly important role in the power system because of its abundant reserves,high technological maturity and easy development.Wind turbines have the outstanding advantages of being clean,efficient and non-polluting renewable.It has gradually replaced traditional power plants,such as thermal power plants,and has become the mainstream choice of power generation equipment.Due to the effects of randomness and wind speed fluctuations,access to a large number of new energies affects the frequency stability of the power system.As the wind turbine operates and participates in frequency regulation,the accumulation of fatigue loads increases,which affects the reliability,economy and safety of the wind turbine.In this thesis,the active power control strategy of the wind farm considering the fatigue load was studied.First,to analyze the effect of various wind speeds and turbulence intensity on the load of the rotating shaft and tower,a comprehensive fatigue evaluation model for wind turbines that can be used for frequency control was established.It provide assistance for follow-up studies.Considering that a wind farm needs to maintain a certain amount of available power to cope with frequency changes,this paper proposes a strategy for allocating active power in a wind farm considering fatigue distribution.This strategy takes into account the increase in fatigue loads while maintaining a certain amount of usage margin in the wind farm.First,the fatigue coefficient of the wind power generator is improved based on the overspeed control operation state of the wind power generator.Second,the minimum standard deviation of the improved fatigue coefficient of the wind turbine was set as the optimization goal,and the activity reference value and the load reduction coefficient of the wind turbine were calculated using the particle group optimization algorithm.Finally,the effectiveness of the proposed method was verified by comparing the accumulated rainfall period of the unit components and the load equivalent to the damage based on the constructed wind farm simulation model.In the particle swarm optimization-based wind farm active power allocation strategy,it use the hybrid gray wolf particle swarm optimization algorithm to optimize the active power output of the wind farm,taking into account the characteristics of the particle swarm optimization algorithm.Compared to the particle swarm optimization algorithm,it has the characteristics of high precision and fast convergence speed.A wind farm frequency controller based on fuzzy evaluation is designed.Using fuzzy evaluation,the capacity weights of devices participating in frequency regulation are calculated based on the device’s fatigue state,available power,speed,and wind speed.When the wind farm needs to increase or decrease the active power output,the priority of the units participating in frequency regulation is determined according to the capacity weighting to respond to the frequency regulation of the power system.Finally,the proposed method is verified through simulation analysis.