摘要
随着火电厂辅机系统变频器的大规模使用,电网电压暂降引起大量火电机组跳闸的问题凸显。结合陕西电网典型火电机组给煤机变频器低电压穿越特性试验现场试验数据,系统地分析了电压暂降主要因素对变频器输出特性的影响,提出采用动态电压恢复器(dynamic voltage restorer,DVR)进行电压暂降快速补偿的方案。电网电压暂降深度、电压暂降持续时间、负载大小、电压暂降类型等因素对火电机组给煤机变频器工作特性影响较大,导致电压敏感设备变频器直流工作电压降低超限甚至失压,进而引发变频器工作回路动作跳闸退出运行。利用PSCAD/EMTDC搭建典型的变频器电压暂降实验及补偿模型,结果表明采用动态电压恢复器能够很好的稳定变频器直流工作电压,有利于提高变频器电压暂降抗扰能力。
As the large-scale usage of auxiliary system inverter in power plants, large tripping problems of thermal power units caused by voltage sag are more and more obvious. Combining with the field test data of low voltage ride through （LVRT） for coal feeder inverter in thermal power units in Shaanxi Grid, this paper analyzed the effect of main factors of voltage sag on the output characteristics of inverters, and used dynamic voltage restorers （DVR） as a rapid compesation method to solve voltage sag. The sag dephth, duration time, load, sag types and other factors had great influence on the operating featuer of coal feeder inverters in thermal power units, which might lead to the DC working voltage of inverter reducing, even triggering inverter circuit tripping out of service. The voltage sag experiments and compensation stimulation model were established with using PSCAD/EMTDC. The results show that DVR have good ability to steady the DC working voltage and can promote inverter through the serious voltage sag.
出处
《电力建设》
北大核心
2015年第3期88-93,共6页
Electric Power Construction
基金
西安工程大学博士启动基金(BS1018)
