基于PCS功率越限判据的独立型微电网紧急控制策略

Emergency control strategy of independent micro-grid based on PCS power limit criterion

紧急控制作为微电网系统的最后一道防线,在系统受到大扰动以后,能够维持频率稳定,对微电网的稳定运行具有重要意义。文中分析了频率紧急控制策略以及轮次减载策略在微电网中存在的定值整定难、无法精准减载的问题,提出了一种基于储能变流器(PCS)输出功率越限判据的独立型微电网紧急控制策略:在外部扰动导致PCS输出功率越限时,通过计及电池荷电状态(SOC)的均衡控制策略计算PCS的越限功率,采用负荷精准减载方案精确切除负荷,并针对工程实施采用面向通用对象的变电站事件(GOOSE)通信技术、提出小步长趋势变化采样算法和防一点大数算法,提高了控制系统的响应速度,提升了大容量独立微电网运行的稳定性。通过新疆某独立型微电网项目工程案例验证了本方案的可行性和有效性。

As the last line of defense of the micro-grid system,emergency control can maintain the frequency stability after the system is greatly disturbed,which is of great significance to the stable operation of the micro-grid.This paper analyzes the problem that frequency emergency control strategy and round load shedding strategy are difficult to set and cannot accurately load down in micro-grid,and an independent micro-grid emergency control strategy based on the PCS output power limit criterion is proposed.When the external disturbance causes the PCS output power to exceed the limit,the PCS's over-limit power is calculated by taking into account the SOC equalization control strategy,the load is accurately cut off by the load accurate load shedding scheme,and adopting GOOSE communication technology for engineering implementation,proposing small step trend variation sampling algorithm and anti-point large number strategy to improve the response speed of control system,improving the stability of large-capacity independent micro-grid operation.The feasibility and effectiveness of this scheme are verified by an independent micro-grid project in Xinjiang.