摘要
风电汇集地区一般地处偏远,电网强度较弱,因此针对弱电网中风机短路故障电流暂态特性的研究十分必要。现有永磁直驱风机交流送出线路对称短路的故障暂态特性的研究很少考虑弱电网中电流对电压的影响及锁相环的锁相准确度,难以精准刻画电流故障特性。该文基于典型电压穿越策略建立PMSG并网模型,充分考虑短路故障后的机端电压幅值、相位跳变与锁相环动态特性,建立了故障过程中电压深度跌落和浅度跌落两种情况下的暂态电流数学模型,利用龙格-库塔算法求出考虑锁相环动态特性的故障电流数值解,揭示了PMSG机端电压与输出电流的相互耦合关系及锁相环动态特性对风机电流的影响机理。研究结果表明该文提出的电流模型更加准确地反映了实际弱电网系统中PMSG的故障暂态特性。
Wind power convergence area is generally located in remote areas with weak grid strength,so it is necessary to study the transient characteristics of wind turbine short-circuit fault current in weak grid.The existing research on the fault transient characteristics of symmetrical short circuit in AC transmission line of permanent magnet direct drive fan seldom considers the influence of current on voltage in weak current network and the accuracy of phase-locked loop,so it is difficult to accurately describe the current fault characteristics.Based on the typical voltage ride through strategy,the PMSG grid connected model was established.Considering the dynamic characteristics of terminal voltage amplitude,phase jump and phase locking loop after short circuit fault,the transient current mathematical model was established under the condition of deep voltage sag and shallow voltage sag.The numerical solution of fault current considering the dynamic characteristics of PLL was obtained by Runge Kutta algorithm,and the coupling relationship between terminal voltage and output current of PMSG and the influence mechanism of PLL dynamic characteristics on fan current were revealed.The results show that the proposed current model can reflect the fault transient characteristics of PMSG in weak power grid more accurately.
作者
盛四清
田颢璟
孙大卫
刘辉
王倩
邢楚铭
SHENG Siqing;TIAN Haojing;SUN Dawei;LIU Hui;WANG Qian;XING Chuming(School of Electrical and Electronic Engineering,North China Electric Power University,Baoding 071003,China;State Grid Jibei Electric Power Research Institute(North China Electric Power Research Institute Co.,Ltd),Beijing 100045,China)
出处
《华北电力大学学报（自然科学版）》
CAS
北大核心
2022年第5期33-41,51,共10页
Journal of North China Electric Power University：Natural Science Edition
关键词
直驱风机
弱电网
低电压穿越
暂态特性
相位跳变
锁相环
PMSG
weak power grid
low voltage ride through
transient characteristics
phase jump
phase locked loop
