基于时间最优的快速平息区间扰动的紧急直流功率控制策略

摘要

为了快速平息交直流互联电网的区间扰动振荡,基于等值两机两区域系统推导了2阶振荡系统的时问最优紧急直流功率支援控制策略.首先采用时间最优控制将相点快速驱动到平衡点附近,然后采用非线性控制对相点进行平衡点镇定控制.为消除直流功率的跃变和高频非线性"颤振"及防止"超调"现象,对开关曲线作了改进,并根据控制相平面推导实现最少次开关切换的直流功率控制量.最后通过仿真验证了该策略的有效性.%Based on the equivalent-two-machine-two-area AC/DC parallel system, a time optimal control(TOC) plan for a second-order oscillation system is developed and a TOC strategy for quickly suppressing interzone disturbance is proposed. Firstly, the TOC theory is introduced to drive system states to a post-fault equilibrium point, and then, the nonlinear control theory is used to hold the states in that equilibrium point. Switching curve is also improved to avoid DC power jump-changing and to eliminate high-frequency nonlinear chattering and overshooting, and the optimal amount of DC power controlled by a minimal number of switching is derived. The simulation results show that the proposed TOC strategy can be combined with the practical DC Emergency Run-up and Run-back control functions to quickly and effectively suppress the interzone oscillation after a first angle swing.