摘要
高压直流(HVDC)换流器阻抗频率特性的确定对避免系统发生谐振具有重要意义。文中提出了基于开关函数理论的HVDC换流器直流等值阻抗和交流等值阻抗计算方法。该方法计及了换流器换相过程的影响,计算换流器的直流等值阻抗时考虑了交流系统的影响,计算换流器交流等值阻抗时考虑了直流系统乃至对侧交流系统的影响。CIGRE first benchmark模型被用于验证该方法。PSCAD/EMTDC仿真和该方法计算得到的阻抗频率特性相吻合。仿真结果证明,直流系统对交流系统的谐振频率有着不可忽略的影响,这种谐振有可能导致直流输电系统的不稳定运行, 而该方法可以准确、方便地计算出谐振频率。
The determination of impedance-frequency characteristic of HVDC converter is important in avoiding system resonance. The paper presents a method to determine equivalent DC impedance and equivalent AC impedance of HVDC converter viewed respectively from DC side and AC side based on switching function theory. In the proposed method, converter commutation course and AC system are considered when calculating equivalent DC impedance, while DC system and the opposite AC system are considered when calculating local equivalent AC impedance. CIGRE first benchmark model is used to verify the method. The frequency characteristic obtained from PSCAD/EMTDC simulation and the method agree well with each other in a wide frequency range. Simulation results also prove that DC system has un-ignorahle impact on AC resonant frequency, which can even result in unstable operation of HVDC system, while the proposed method can predict the resonance frequency conveniently and precisely.
出处
《电力系统自动化》
EI
CSCD
北大核心
2006年第12期66-69,91,共5页
Automation of Electric Power Systems
