Research On Fast Frequency Control Of Hybrid Photovoltaic-Thermal Power Plants System

One of the important indexes to evaluate the stability of power system is frequency,which reflects the balance relationship between active power output and load demand of power system.With the development of renewable energy power generation technology,the proportion of renewable energy power plant in the whole power plant system will continue to increase.As one of the technologies with rapid development of renewable energy power plant technology,The installed capacity of photovoltaic(PV)power plant is increasing in recent years.However,after PV power plant connect to the grid,there must be some random fluctuations to affect the balance between the output of the system active power and load demand.Therefore,when a serious active gaps happen,if there isn’t enough active power to achieve the balance,the frequency will fall sharply,and there must occur a serious harm in the grid.Therefore,it is of great significance to study the fast frequency control strategy of the Hybrid power plants system and fully explore the frequency response capability of the system.In order to fully explore the fast frequency response capability of the Hybrid power plants system.The main research content of this paper includes four parts:In the first part,a thermal power unit model is established,and Digital Electro-hydraulic(DEH)and Coordinated Control Strategy(CCS)are used to realize the primary frequency regulation of thermal power plant together.In the second part,the model of the hybrid power plants system is established,and a fast frequency control strategy for photovoltaic power plant is proposed.In the third part,the model of the hybrid power system is simplified based on the method of system identification and model reduction.In the fourth part,a frequency control strategy based on the integrated adaptive dynamic programming algorithm is proposed for the Hybrid power plants system,and the central error entropy is adopted as the performance index for the problem that the grid frequency is non-Gaussian distribution.The simulation experimental results show that the presented frequency control strategy not only significantly reduce the frequency response time of hybrid power system,but also reduce the error of frequency nadir,so the strategy for realizing the fast frequency control of hybrid power plants system is effective.