摘要
以乌东德电站送电广东广西特高压多端柔性直流示范工程为研究对象,考虑混合三端柔性直流输电系统因受端不同位置交流故障所致的直流过电压,提出相应的故障穿越协调控制策略。在受端主站发生网侧交流瞬时故障的情形下,通过设计混合型模块化多电平电压源换流器全桥子模块自适应负投入策略,实现了利用子模块电容短时过电压储能的能力来快速补偿站间直流电压的上升;短暂时延后,送端电网换相换流器通过定量调整电流指令值策略来减小子模块的不平衡充电功率。在受端主站发生阀侧交流故障的情形下,优先利用输电健全极的功率转代裕度来消纳故障极的部分不平衡功率;同时,故障极从站跟随主站半压运行,相应的高低压阀组切换至定电流及定电压模式,最终实现抑制站间过电流及减小盈余功率。仿真结果表明,2种故障条件下,所提的协调控制策略均可较快实现故障期间的功率平衡,有效抑制仅配备稳态基本协调控制策略下系统所出现的直流过电压现象,同时也基本维持了送端的总体有功传输容量。
The paper takes the UHV multi-terminal flexible DC demonstration project from Wudongde power station to Guangdong and Guangxi as the research object.After considering the DC overvoltage caused by AC faults at different positions of hybrid three-terminal flexible DC electric power transmission,to address this issue,the corresponding coordinated control strategy for fault crossing is proposed.In the case of transient AC fault on the network side of the main station at the receiving-end,an adaptive negative input strategy is designed for the full-bridge sub-module of the hybrid modular multilevel voltage source converter,which can quickly compensate the rise of DC voltage between stations by utilizing the ability of short-time over-voltage energy storage of sub-module capacitor.After an instant time delay,the unbalanced charging power of the sub-module can be reduced by adjusting the current instruction value strategy from the commutation converter at the sending terminal.In the case of AC fault on the valve side of the main station at the receiving-end,the partial unbalanced power of the fault pole is absorbed by the power transfer margin of the transmission sound pole,and at the same time,when the fault pole slave station runs with the main station at half voltage,the corresponding high and low voltage valve sets switch to the constant current and constant voltage modes,and finally realize the suppression of over-current between stations and reduce surplus power.The simulation results show that the proposed coordinated control strategy can achieve the power balance faster during the fault period under both fault conditions;the DC over-voltage of the system with the steady-state basic coordinated control strategy is effectively suppressed,and the total active power transmission capacity of the transmitter is basically maintained.
作者
王成磊
濮永现
黄力文
唐岚
陈有为
胡红文
魏可佳
WANG Chenglei;PU Yongxian;HUANG Liwen;TANG Lan;CHEN Youwei;HU Hongwen;WEI Kejia(School of Electric Power Engineering,Kunming University of Science and Technology,Kunming 650051,China;Power China Kunming Engineering Corporation Limited,Kunming 650051,China;Qujing Power Supply Bureau of Yunnan Power Grid Co.,Ltd.,Qujing 655100,China)
出处
《电力科学与工程》
2024年第4期31-43,共13页
Electric Power Science and Engineering
基金
国家自然科学基金资助项目(52037003)
云南省重大科技专项计划(202002AF080001)。
关键词
特高压直流输电
多端柔性直流输电
受端交流故障穿越
直流过电压抑制
站间协调控制策略
ultra high-voltage direct current power transmission
multi-terminal flexible DC transmission
AC fault crossing at the receiving-end
DC overvoltage suppression
coordinated control strategy between stations
