适用于多机集群的外部集中扰动式阻抗测量孤岛检测法  

An Islanding Detection Method Based on Impedance Estimation Using External Centralized Disturbances for Multi-Distributed Generation System

作　　者：贾科 郇凯翔 魏宏升 毕天姝 何国庆[2] 

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学)北京102206 [2]国家电网公司北京100192

出　　处：《电工技术学报》2016年第13期120-129,共10页Transactions of China Electrotechnical Society

基　　金：国家重点基础研究发展(973)计划(2012CB215206);国家自然科学基金(51407067);中央高校基本科研业务专项资金(2014MS07;2016ZZDS01);青海省光伏发电并网技术重点研究室(2014-Z-Y34A)资助项目

摘　　要：现有逆变器并网类新能源电源孤岛检测多采用主动法,但由于多个机组并网时扰动信号相互影响,存在检测盲区,同时可能影响系统电能质量。基于此,提出了一种可同时适用于单机和多机集群的有源孤岛检测方法,采用外部集中扰动方式,避免了多机扰动信号相互干扰,且可普适于逆变器并网类电源、同步发电机等多种类型电源,同时提出了逆变器并网类电源在外来扰动下的测量阻抗模型。利用宽频脉冲注入及高频电抗计算放大了孤岛前后特征量差异,提高了检测灵敏度。另外,通过间歇性过零点短时注入控制,提高了阻抗测算准确度,并降低了主动法对系统的扰动,保证了良好的电能质量,同时降低了对注入装置直流电压等级的要求,保证了实用性和经济性。Active detection methods are mostly employed in existing islanding detections for renewablepower generations which are connected to the grid through inverters. But, due to the m utual interferences of the irdisturbance signals, there might be a non-detection zone when multiple generations or inverters are connected tothe grid. And also, this would bring bad influences on the power quality of the system. In view of the issuesabove, an active islanding detection method suitable for both single distributed generator （ D G ） a n d m ultiple-D G scluster is put forward in this pa pe r, w hich can avoid the m utual interferences of m ulti-supp ly disturbancesignals. In a d d itio n , it is universally applicable for different types of D G s , includ in g the grid-connected inverterand the synchronous generator, etc. M eanw hile, the measured impedance model for the grid-connected inverter isproposed under circumstances of the external disturbance signals. The characteristic quantity distinction before andafter islanding is am plified by using the wideband spike pulse injection and the high-frequency reactanceca lculation , which improves the detection sensitivity. Moreover, by means of the interm ittent zero-crossing-point（ ZCP） injection control proposed in the paper, the method improves the accuracy of the impedance estim ation,reduces the disturbances to the power system caused by the active detection m ethod, and ensures favorable powerquality. M eanw hile, the control lowers the requirem ent for the DC voltage level of the injection device, whichensures the pra cticab ility and economy.

关 键 词：孤岛检测 主动注入法 多机集群逆变器 阻抗模型 高频电抗计算 

分 类 号：TM77[电气工程—电力系统及自动化]