摘要
高压直流输电系统直流闭锁引起的送端交流母线暂态过电压可能影响送端风火打捆交流系统风电机组的稳定运行。针对该问题,首先分析了直流闭锁引起暂态过电压的主要原因及其对风电机组造成的影响,然后阐述了直流闭锁动态过电压及保护动作过程,并利用由PSCAD中自带示例Cigre_Benchmark改进的双极高压直流输电系统模型仿真分析了直流闭锁的触发方式及其引起暂态过电压的过程机理。通过改进触发直流闭锁的紧急停机策略,减缓直流闭锁的触发过程,改变保护措施的触发顺序,并与安全控制系统配合来抑制送端并网母线的暂态过电压,以此来保证风电机组的稳定运行。基于PSCAD/EMTDC搭建了风火打捆高压直流模型,最后通过算例仿真证明了所提方法的有效性。该方法对于风火打捆高压直流输电系统的电压稳定性研究具有一定的参考价值。
The transient overvoltage of converter side AC bus caused by DC block may influence the stable operation of wind-thermal-bundled AC system wind turbines. To solve this problem, this paper firstly analyzes the main reasons of transient overvoltage caused by DC block and its impact on wind turbines. Then dynamic overvoltage caused by DC block and protection operating process are expounded. Besides, the HVDC system model called Cigre_Benchmark in PSCAD is modified, and the modified model is used to simulate and analyze the trigger mode of DC block and the process mechanism of transient overvoltage. The emergency switch off sequence strategy triggering DC block is improved, the triggering process of DC block is retarded, and the trigger sequence of protection measures is changed. And the former strategy works with safety control system to suppress transient overvoltage of the grid-connected bus of converter side, by which the steady operation of wind turbines is guaranteed. The wind-thermal-bundled HVDC model is built based on PSCAD/EMTDC. Finally the effectiveness of the method mentioned is proved by example simulation. This method has certain value for the study of voltage stability of wind-thermal-bundled HVDC system.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2018年第5期99-105,共7页
Power System Protection and Control
基金
新能源与储能运行控制国家重点实验室(中国电力科学研究院)开放基金资助
关键词
直流闭锁
暂态过电压
并网母线
紧急停机策略
风火打捆高压直流输电系统
DC block
transient overvoltage
grid-connected bus
emergency switch off sequence strategy
wind-thermal- bundled HVDC system
