含新能源接入的双极柔性直流电网运行特性研究与工程实践

Operating Characteristics Research and Engineering Applicationof Voltage Source Converter Based DC GridWith Renewable Source Connected

作为一种新的电网型式,直流电网与端对端柔性直流工程具有不同的特点。结合世界上首个柔性直流电网工程—张北柔性直流电网试验示范工程,分析了直流电网的稳态和动态运行特性,建立了直流电网的稳态和动态分析模型;然后提出了直流电网的故障防御标准,对直流电网线路故障、换流器故障、直流母线故障等故障特性进行了深入分析,提出了各类故障的处理策略;最后提出了直流电网的控制策略。所开展的研究应用到张北柔性直流电网试验示范工程的建设中,并对后续直流电网工程具有重要的参考意义。

As a new type of power network,the voltage source converter based high voltage direct current(VSC-HVDC)grid has many different characteristics from the point-to-point VSC project.Combining the first VSC-HVDC grid project in the world—Zhangbei VSC-HVDC grid demonstration project,the steady-state and dynamic characteristics of the dc grid are analyzed,and the steady-state and dynamic models are established.Then,the fault prevention standard is proposed,and also the characteristics of dc line fault,converter fault,and DC bus fault are analyzed,based on which the fault handling strategies are proposed.Finally,the control strategies of the dc grid are proposed.The research results have been applied in the construction of Zhangbei VSC-HVDC grid demonstration project,and is of significance to the construction ofthe following VSC-HVDC grid projects.