考虑AGC指令随机特性的火-储混合电站二次调频研究

Secondary frequency regulation of a hybrid coal-fired generator and BESS power station considering random characteristics of AGC instructions

首先,对如何利用电池储能系统(battery energy storage system, BESS)提升火电机组的二次调频能力进行了研究。其次,基于实测自动发电控制(automatic generation control, AGC)指令,对AGC指令持续时间、间隔时间、调节速率与调节方向的概率特性进行了建模。AGC指令调节方向随机,BESS辅助火电机组二次调频时,将在充放电状态间频繁切换,快速耗尽电池循环寿命。为解决这一问题,将BESS分组接入调频电厂,运行中两组BESS处于不同充放电状态,分别用于响应AGC升指令与降指令,一旦任意一组BESS满充或满放,立即同时切换两组BESS的充、放电状态。然后,采用序贯蒙特卡洛模拟(sequential monte carlo simulation, SMCS)方法对火-储混合电站典型日的运行状况进行了模拟,并在此基础上评估二次调频性能、估算BESS循环寿命损耗。最后,基于某实际调频电厂的仿真实验表明:BESS可显著增加调频机组的二次调频性能,且所提策略能有效减少BESS循环寿命损耗。

First,this paper focuses on how to use a battery energy storage system(BESS)to enhance performance in secondary regulation of a coal-fired generator.Second,the probability characteristics of automatic generation control(AGC)instruction duration period,interval period,regulation rate and regulation direction are modeled based on real AGC instructions.AGC instructions with random regulation direction will lead to frequent switching between charging and discharging states of the BESS,thus quickly depleting the battery.To address this problem,the BESS is divided into two parts when connecting to the frequency regulating generator.The two parts of the BESS are respectively in charging and discharging states for supporting up and down AGC instructions.Once any part of the BESS arrives at full charge or discharge,two parts of the BESS switch their charging/discharging states immediately.The performance on secondary frequency regulation of the coal-fired-generator with the BESS and tearing losses of the BESS are estimated based on simulating the operation of a hybrid coal-fired-generator and BESS power station during a typical day by the sequential Monte Carlo simulation(SMCS)method.Finally,the simulation experiments based on a real frequency regulating generator show that BESS can enhance performance on secondary regulation of the frequency regulating generator and the strategy developed in this paper can effectively reduce cycle life loss of the BESS.