Selection And Optimization Of Energy Storage Battery Participates In Power Grid Rapid Frequency Regulation

With the rapid development of random energy and volatility of new energy power generation,it will endanger the stability of the grid when large-scale on-grid.Using the energy storage system to quickly and accurately control the bi-directional power throughput capacity and realize the space-time translation of the electric energy to improve the performance of frequency regulation and the grid stability.In this paper,under the circumstance of energy storage involved in the application of grid frequency regulation,studies the comprehensive selection of energy storage battery,and explores the control methods considering the rate capability of common energy storage in grid frequency regulation.Finally,as example for lithium titanate battery of which to participate in the entire process of frequency regulation analysis explore the type selection and capacity configuration o ptimization in high-rate characteristics.First of all,based on the different characteristics of energy storage batteries,the paper studies the selection of energy storage batteries involved in the frequency regulation of power system from the aspect of technical and economic.Summarize and extracting the indexes of technical and economic for different types of energy storage batteries,sort and select by AHP(Analytic Hierarchy Process)in technically,and get the result of economically sorting use that annual average method.The results of the technical / economic selection rankings weighted computing,to have the results of technical and economic optimal comprehensive selection,and sensitivity analysis of the various cost factors,summed up the impact of various types of energy storage economy sensitive factors.Finally,according to the typical scenario of frequency regulation,we select the Li-ion,PHS(Pumped Hydro Storage)and CASE(Compressed Air Energy Storage)as the technically superior energy storage solutions.CASE,Flywheel and LAB(Lead-Acid Battey)are dominant economically plans.CASE,Li-ion,PHS is the optimal solutions for technology and economy.It further reduces the power cost of Li-ion by sensitivity analysis,making it the optimal energy storage power supply for both technology and economy.Then,based on the rate characteristics of the energy storage battery,the opt imal operation control of the energy storage battery is designed.This method is based on the relationship between charge / discharge times and magnifications of various types of storage batteries,and takes the minimum capacity of storage batteries as the goal,optimizes the configuration differences of storage batteries involved in power grid frequency regulation under different control strategies.This method can effectively screen out the battery type with good rate characteristics and its matching cont rol strategy.Finally,taking the conditions of typical peak load and non-peak load in grid as an example,and considering with the equivalent conversion time under different rates.We consider the rate characteristics under three control strategies: inert ial-droop control,power-droop control,and droop control,and lithium iron phosphate,lithium titanate,lead storage battery capacity configuration for comparative analysis.The results show that the lithium titanate battery with high-rate factor under inertial-droop control has the lowest capacity,which verifies the feasibility and effectiveness of the optimized control method.Finally,in view of the conflict between the larger frequency regulation demand and the opportunity cost of frequency regulation capacity in the small probability emergency(extreme)accident,based on the obtained energy storage selection and optimized control method,the high power lithium titanate battery is selected and th e optimized capacity for frequency regulation process is studied.Based on the analysis of the characteristics of primary and secondary frequency regulation coupling process,a method of energy storage participating in the whole frequency regulation of the power grid was established.Based on this,the charge / discharge ratio characteristics of lithium titanate batteries and the equivalent conversion time under different rates,forming a capacity configuration flow that takes into account the rate characte ristics of the energy storage battery.The case of an emergency(extreme)accident(sudden trip of generator or sudden load increase)is verified and simulated by an example.The results show that under the same disturbance condition,considering the rate characteristics of lithium titanate battery,the required configuration capacity is significantly reduced.The simulation results verify the effectiveness of the proposed method and the advantages of lithium titanate batteriy with high rate characteristics.