新型混合直流输电方式的研究

Research on a Novel Hybrid HVDC System

传统高压直流输电(HVDC)系统具有技术成熟、成本低廉的优点和需要吸收大量无功功率以及存在换相失败的危险等缺点;基于电压源换流器(Voltage Source Converter,VSC)的高压直流输电系统具有运行控制方式灵活的优点和相对成本较高的缺点。文中提出一种结合二者优点的新型混合直流输电方式,其送端采用传统HVDC 的相控换流器,受端采用VSC。仿真结果表明,这种混合直流输电系统可稳定地进行电力传输,且当交流系统发生单相接地故障和三相短路故障后,仍可以迅速恢复系统的稳定运行。

Conventional HVDC has the advantages of mature state of art and lower cost and the disadvantages of absorbing large reactive power and the danger of commutation fault. Voltage Source Converter （VSC） based HVDC （VSC-HVDC） has the advantages of flexible operation and control and the disadvantages of high cost. Combining the advantages of the two kinds of HVDCs, a novel type of hybrid HVDC transmission is proposed, in which at sending terminal the Phase Control Converter （PCC） is adopted and at receiving terminal the VSC is adopted. Simulation results show that the proposed hybrid HVDC system could operate steadily. Further more when single phase to ground or three phases short circuit fault occurs in one or both AC sides, the steadily operation of the proposed hybrid HVDC can he rapidly restored.