摘要
系统的大功率缺额易引起较大的频率偏移。频率偏移过大可能导致直流系统(high voltage DC transmission,HVDC)触发脉冲异常,进而引发运行问题。以实际系统MACH2(modular advanced control hardware 2)为例,分析了触发控制原理及锁相环工作原理,重点研究了系统频率变化对锁相环工作及换相电压过零点判断的影响。在PSCAD/EMTDC仿真平台中搭建了MACH2触发环节的简化模型,仿真结果表明,频率变化会影响系统触发脉冲的产生,导致实际触发延迟角无法及时跟踪指令值,但对系统运行的影响不大。由于控制系统触发延迟角幅值限制环节的影响,系统频率升高及降低两种情况对直流系统的影响程度也有差别。
Severe power outage is easy to cause obvious grid frequency deviation, and too large frequency deviation may lead to abnormal triggering pulse in HVDC power transmission system and further causes the troubles in the operation of HVDC transmission system. Taking an actual system MACH2 （modular advanced control hardware 2） as example, the principle of trigger control and the working principle of phase-locked loop are analyzed, and the impacts of power grid frequency deviation on the working of phase-locked loop and the judgment of zero crossover points of the commutation voltage are emphatically researched. In PSCAD/EMTDC simulation platform a simplified model of the triggering link of MACH2 is constructed, and simulation results show that power grid frequency deviation affects the generation of system triggering pulses and makes the actual firing delay angle not be able to track the value of the reference in time, however is slightly affects the system operation. Due to amplitude limiter of firing delay angle in the control system, the impact of grid frequency increase on HVDC transmission system differs from the impact of grid frequency decrease.
出处
《电网技术》
EI
CSCD
北大核心
2014年第4期871-876,共6页
Power System Technology
关键词
系统频率
直流输电
触发控制
锁相环
换相电压过零点
power grid frequency
HVDC power transmission
trigger control
phase-locked loop
zero crossover points of commutation voltage
