高压直流输电系统吸收与并联电容换相换流器特性分析

The Characteristic Analysis of HVDC System with Absorption and Shunt Capacitance Commutated Converter

为改善高压直流输电(HVDC)换相特性及调节无功分布,提出一种HVDC系统吸收与并联电容换相换流器(ASCCC)。首先给出其拓扑结构和数学模型,以及系统改善换相特性的工作原理;然后通过构建等效电路,研究并联电容分流特性,以及对比研究传统和新型换相换流器的无功特性,推导出其无功计算方法;最后以某±800kV特高压直流输电工程为例,搭建基于ASCCC的逆变站的Matlab仿真模型,同时进行原理样机实验。结果表明ASCCC不仅具有减少逆变器换相失败的优点,而且能够优化换流变压器乃至整个系统的运行状态。

In this paper,a novel HVDC system absorption and shunt capacitance commutated converter(ASCCC)was given to improve the commutation characteristics of HVDC transmission and adjust the reactive power distribution.First,the topology and mathematical model were given,also the working principle of the system to improve commutation characteristics;then,by constructing the equivalent circuit,the shunt characteristics of the shunt capacitor and the comparative study of the reactive characteristics of the conventional and novel commutated converters were given,and the reactive power calculation method was deduced;finally,taking a±800kV UHVDC transmission project as the research object,the simulation model of the inverter station using ASCCC was built by Matlab,the prototype experiment was conducted,and the results show that ASCCC not only has the advantage of reducing the commutation failure of the inverter,but also can optimize the operation status of the converter transformer and even the entire system.