Grid Connected Reliability Evaluation Method Of Photovoltaic Power Station With Energy Storage

With the transformation of China's clean energy,large-scale renewable energy such as photovoltaic combine to the grid.Photovoltaic has the characteristics of randomness and intermittent witch make large influence on the safe operation of the power grid and power quality.Therefore,evaluation of the grid-connect capability of PV is the important premise of photovoltaic power station safety combined to the grid and need to analysis the impact on the reliability of the system correctly.At present,the reliability evaluation of PV power plant itself mainly to calculate the incredible capacity of the main capacity of photovoltaic power generation,but it can only get a definite indicator for the evaluation of PV power plant and grid-connect reliability.In order to improve and perfect the reliability evaluation index of grid-connected PV power plant,this paper presents a method of reliability interval calculation method for PV power plant.According to the above problems,this paper analyzes the weather characteristics of the historical power generation data of photovoltaic power station,and divides the weather into four types like sunny,cloudless,cloudy and rainy by fuzzy C-means clustering method,and established a multi-state transfer model of PV power plant firstly.Secondly,the IEEE-RTS reliability test system is established based on the former model and the Sequential Monte Carlo method is adopted to evaluate the reliability index impact after the PV plant connect to the grid,and a calculation method of grid-connection reliability limit of PV power generation is proposed in this paper Finally,in order to improve the grid-connected capacity of PV plant,energy storage system is used to reduce the active power fluctuation rate of PV,and the quartile method is used to calculate grid-connected reliability limit value.Based on this,an interconnection reliability calculation method of photovoltaic power generation system is proposed.The results show that the generation system combined with PV and energy storage system can effectively reduce the fluctuation of active power output of PV and improve the capability of grid-connected.In the planning of power dispatching plan,it can make an effective pre-judgment to the reliability of the PV plant combined with the weather forecasting and provide the theoretical basis for the dispatcher to make plan and power dispatch.