WANG Yuhong, LI Tianze, ZENG Qi, et al. 实际运行点动态修正的VSC-MTDC改进下垂控制策略[J]. 2018, 44(7): 2133-2142.
DOI:
WANG Yuhong, LI Tianze, ZENG Qi, et al. 实际运行点动态修正的VSC-MTDC改进下垂控制策略[J]. 2018, 44(7): 2133-2142.DOI:
实际运行点动态修正的VSC-MTDC改进下垂控制策略
摘要
针对传统下垂控制因下垂系数设置不当而产生的换流站过载及运行损耗较高现象
提出一种改进下垂控制策略。该控制策略综合考虑运行损耗与换流站功率裕度
建立运行损耗最小时的最优潮流与优化下垂系数间的关系
推导得到经济分布的下垂系数
并将该下垂系数与考虑功率裕度的下垂系数进行加权平均。同时设置低压加速因子
使得换流站动态修正实际运行点
在直流电压偏高时以具有功率裕度为主控制目标
直流电压偏低时以具有最小运行损耗为主控制目标。最后
在PSCAD/EMTDC仿真平台中搭建五端柔性直流输电系统
仿真结果表明:改进下垂控制后
换流站能够针对运行工况的改变
协调保有功率裕度与降低系统运行损耗控制目标
实现了运行点的动态修正。仿真结果与理论分析一致
证明了所提控制策略的有效性。
Abstract
Traditional droop control may cause problems such as station overload and increase in system loss with inappropriate DC voltage droop coefficient. In order to solve these problems
we proposed an novel droop control strategy
in which the system loss and station headroom are considered simultaneously to calculate the weighted average number of the droop coefficients after considering headroom of VSC and optimal power flow under minimum system loss respectively. Meanwhile
setting low-pressure acceleration factor makes VSC to emend the operation point dynamically. The available headroom is regarded as a main control target with relatively high DC voltage
and the minimum system loss is regarded as a main control target with relatively low DC voltage. Finally
we established a simulation model of five-terminal VSC-HVDC in PSCAD/EMTDC. The simulation results indicate that VSC can coordinate the control targets of available headroom and minimum system loss with novel droop control strategy according to the change of operation condition
and realize the dynamically corrected operating point. The expected performance of theoretical analysis verifies the effectiveness of the proposed strategy.