Research On Energy Storage Participating In Active Power Dispatching Strategies Of Grid Under High Wind Penetration

In order to relieve the pressure of energy and environment,large-scale wind power has been used in power system.However,wind power fluctuations and intermittency has brought new challenges to the security and stability of power system.With the increase of wind power penetration,the problems that frequency stability of power system and daily schedule arrangement of wind farm are getting worse.As an emerging resource,energy storage has many advantages of environmental-friendly,flexible charging and discharging,high reliability of power supply and fast response speed.It can jointly dispatch with wind power and traditional units to improve the stability and economy of power system.The strategy of energy storage participating in active power dispatching of power system has become a research hotspot at home and abroad which is meaningful.The study of energy storage participating in active power dispatching under high penetration of wind power is proposed in the thesis.Firstly,the uncertainty mechanism of wind power and stochastic programming theory are analyzed.At the same time,the influence of wind power uncertainty on power system frequency stability and active power dispatching is studied.Then,a three-stage of joint scheduling model of wind energy storage hybrid system is established,which provides a reference for the daily schedule of the wind farm.Finally,the strategies of energy storage participating in automatic generation control of thermal power plant and economic research are proposed,which provide theoretical guidance for the energy storage configuration of thermal power plants.The main contents of this thesis are organized as follows.(1)Considering the uncertainty of wind power,the generation and reduction technology of wind power scenario is proposed.Then the effect of the increase of wind power penetration on the frequency stability of power system is analyzed by the classical two area model.At the same time,the influence of large-scale wind power on active power scheduling of power system is studied,which lays a good foundation for establishing wind energy storage joint dispatching model and energy storage model for improving AGC performance of power plant.(2)For the wind farm,firstly,the probability distribution function of wind power prediction error is researched and a wind power forecasting error correction model is established.Based on this,a scheduling model of day-ahead-intraday-realtime three-stage wind energy storage hybrid system is established,which provides a reference for the arrangement of day-ahead and intraday dispatching plan and charge and discharge power of energy storage as well as abandoning wind power in real time.The case study shows that the participation of energy storage in wind farms can effectively increase the net profit of wind farms,reduce the penalty of output deviation and reduce the amount of abandoning wind power.At the same time,the sensitivity analysis of the effect of various penalty factors on wind farm net income is carried out.(3)For the thermal power plant,firstly,the calculation method of the frequency control performance index of the thermal power units in the compensation policy is analyzed.At the same time,strategies of energy storage charging and discharging are proposed to improve AGC performance.Finally,considering the influence of charging and discharging frequently on its life,an economic model of energy storage participating in the frequency control of thermal power units is established.And the optimal energy storage capacity is calculated by the differential evolution algorithm(DE).The case study shows that the proposed charge-discharge strategies can effectively improve the AGC performance of thermal power units and prolong the service life of energy storage,which brings significant benefits for thermal power plants.