水电孤岛高压直流送出协调控制策略

高压直流输电送端处于孤岛模式时,系统稳定性较差.由于送端与交流主网没有电气联系,在遭受故障的情况下,功率的不平衡可能导致发电机超速.针对水电孤岛高压直流送出系统提出了一种协调控制策略.基于高压直流功率调制机制和水轮机调速系统的研究,在提升高压直流输送功率的基础上,通过注入一个经 PI 环节优化的输送功率减少量,对原有的闭环控制策略进行了修改.在 PSCAD/EMTDC 电磁暂态仿真环境下搭建了水电孤岛高压直流送出的模型,并通过仿真验证了所提出的协调控制策略的有效性

A Coordinated Control Strategy for HVDC Sending System Under Islanded Hydropower Station

When the sending end of HVDC power transmission system falls into islanded condition,the stability of the HVDC transmission system deteriorates.In view of the fact that the sending end is not directly connected to AC main system,so the unbalance of power due to the islanded operation of hydropower station leads to over-speed of hydrogenerator.In allusion to the islanded hydropower station,a coordinated control strategy for the HVDC sending system is proposed.Based on the research on mechanism of DC power modulation and hydro turbine governing system,on the basis of increasing the power transmission by HVDC system,the original closed-loop control strategy is modified by injecting a transmitted power decrement that is optimized by PI controller.In the electromagnetic transient simulation environment based on PSCAD/EMTDC an HVDC sending system under islanded hydropower station is built and effectiveness of the proposed coordinated control strategy is verified by simulation results.