基于暂态能量函数优化VDCOL对提高弱送端系统稳定性的研究

文章以锡盟-泰州特高压弱送端交流系统为背景，提出优化低压限流控制环节（voltage dependent current order limiter ，VDCOL），以提高系统的稳定性。首先分析传统VDCOL的工作原理及局限性，提出以送端短路比与受端换流母线电压作为VDCOL截止电压的变量，进而达到优化VDCOL的作用。使其截止电压为随逆变侧换流母线电压变化而变化的数值，可以兼顾交流与直流系统的恢复速度。其次，详细分析构建考虑直流系统动态特性的暂态能量函数的过程，并采用实时数字仿真仪（real time digital simulator，RTDS）搭建单机无穷大-直流的仿真算例。最后，基于时域仿真及暂态能量函数裕度方法，验证优化直流控制系统中的低压限流控制环节对送端交流系统稳定性的改善作用。

Optimization of VDCOL Based on Transient Energy Function Analysis to Improve Stability of Weak Delivery System

On the background of the Ximeng-Taizhou UHV weak delivery end AC system， this paper proposes an optimized voltage-dependent current order limitation control link （OVDCOL）. This paper firstly analyzes the working principle and limitations of the traditional VDCOL， and proposes to use the short-circuit ratio of the transmitting end and the voltage of the converter busbar at the receiving end as the input value to change the VDCOL cut-off voltage， so as to optimize the VDCOL effect. The cut-off voltage is a value that varies with the voltage of the converter busbar on the inverter side， and the control strategy of the system and DC fast recovery can be considered. The process of constructing the transient energy function considering the dynamic characteristics of the DC system is analyzed in detail， and the real-time digital simulation software RTDS is used to build a single-machine infinite DC simulation example. The time domain simulation and the transient energy function margin method are used to verify the optimized DC control. The voltage-dependent current order limitation control link in the system improves the stability of the delivery system.