750 kV GIS设备母线拓扑结构对VFTO影响研究

Research on the Influence of 750 kV GIS Bus Topology Structure on VFTO

GIS变电站中隔离开关和断路器的操作会产生波头极陡并伴有高频振荡的快速暂态过电压(VFTO),对GIS设备运行的可靠性以及内外绝缘构成很大的威胁。现有研究表明GIS变电站拓扑结构对VFTO的幅值及频率特性有着较大的影响,而工程上主要关注VFTO沿线最大峰值的变化规律。为此从GIS变电站简化模型着手,分析研究VFTO的幅值以及频率特性随母线、分支母线长度变化的一般规律。在此基础上,通过ATP-EMTP电磁暂态仿真软件对青海某750 kV GIS变电站进行隔离开关分闸以及不对称故障下的站内各节点VFTO幅值变化规律的仿真研究,以得到拓扑结构的优化设计建议。

The operation of the isolating switch and circuit breaker in the GIS substation will produce a fast transient over-voltage(VFTO)with extremely steep wave head and high-frequency oscillation,which poses a great threat to the reliability of GIS equipment operation and internal and external insulation.The existing research shows that the GIS substation topology has a great influence on the amplitude and frequency characteristics of VFTO,and the engineering focuses on the variation of the maximum peak value along the VFTO.To this end,the author starts with the simplified model of GIS substation,and analyzes the general law of the amplitude and frequency characteristics of VFTO with the length of bus and branch bus.On this basis,the ATP-EMTP electromagnetic transient simulation software is used to simulate the isolation of the 750 kV GIS substation in Qinghai and the VFTO amplitude variation of each node in the station under asymmetric fault to obtain the optimal design of the topology.