HVDC故障恢复特性的分析及改善措施

为了探究影响高压直流输电(HVDC)故障恢复特性的主要因素及改善其恢复特性的措施,文章分析了包括交流系统强度、直流输电极控制中相关参数的设置及故障恢复期间交流系统的无功补偿特性在内的各种因素在系统切除故障后对电压及功率恢复的影响,提出了包括AC-VDCOL与DC-VDCOL相结合的低压限流环节(VDCOL)并且在故障恢复期间改变VDCOL的特性曲线,增大系统故障期间熄弧角整定值的优化控制、采用SVC进行无功补偿等措施来改善HVDC故障恢复特性。利用PSCAD/EMTDC仿真软件在CIGRE直流输电标准测试系统中进行故障仿真。结果表明当系统发生故障时,交流系统强度越强越有利于系统故障后电压及功率的恢复,采用SVC无功补偿、优化的低压限流环节和熄弧角控制有利于改善故障的恢复特性。

HVDC Fault Recovery characteristics and enhancement methodologies

In order to research the main factors influencing the fault recovery of high-voltage direct current transmission(HVDC) and the improvement measures, this paper analyzes a variety of factors influence the recovery of voltage and power after the fault cleared, including the strength of AC system, the polar control setting of DC transmission system and the reactive properties of AC system, meanwhile, a series of measures improving the fault recovery including improving voltage dependent current order limiter(VDCOL), optimizing arc extinguishing angel control and adopting SVC reactive power compensator are proposed. This paper do the fault simulation with PSCAD/EMTDC based on CIGRE benchmark mode. The result shows that the stronger the AC system is, the more beneficial the recovery of voltage and power, meanwhile, proves that it is useful for improving fault recovery to adopt SVC reactive power compensator, optimized voltage dependent current order limiter and modified arc extinguishing angel control.