500kV线路高抗退出运行及选择备用电磁暂态

电网500 kV线路高抗故障率较高,同时电网结构、运行方式变化较快,高抗原始配置条件发生改变。因此对广东500 kV主通道高抗退出可行性及全网选择一组备用高抗进行电磁暂态研究,重点研究线路高抗运行和退出工况下的工频过电压、合闸及单相重合闸操作过电压、潜供电流和恢复电压以及甩负荷操作过电压等,并对系统运行、操作方式提出要求。研究成果对于电网资源综合利用、设备优化配置和节约运行成本意义较大,已实际应用于广东电网,并对全国省级电网具有借鉴价值。     

1000kV交流试验示范工程的过电压实测

在1 000 kV长治—南阳—荆门特高压交流试验示范工程系统调试中,通过对3个变电站(开关站)主要电气设备及线路的暂态电压和暂态电流进行测量,可以确定工程设计是否安全可靠,为今后特高压工程的设计和运行提供参考。测试包括投切空载变压器、投切低压电抗器、投切空载线路、投切低压电容器和人工单相瞬时接地。测试中的暂态过电压、暂态电流最大值均未超过设计和规程允许值。     

磁环抑制GIS中特快速暂态过电压的模拟试验和仿真

封闭式组合电器（GIS）中隔离开关操作空载短母线时产生的特快速暂态过电压（VFTO）有可能在GIS及其相连设备引起故障，已有的VFTO抑制方法存在种种不足，文中提出采用磁环抑制GIS中的VFTO。模拟试验证明磁环可以有效抑制VFTO。考虑磁环的饱和、滞回、损耗特性，应用Jiles—Atherton模型对磁环仿真，模拟试验电路的仿真结果和试验结果基本符合，验证了模型的正确性。对磁环磁化过程的分析表明，磁环在动态磁化过程中储存和消耗了行波能量，从而降低了VFTO的幅值、加速了VFTO的哀减、降低了VFTO的陡度。应用这一模型计算了大亚湾电站GIS系统中加入磁环前后的VFTO，结果表明磁环对VFTO有明显抑制作用。     

Overvoltages in High-Frequency Stopper Circuits

Transient processes in stopper circuits experiencing impulse overvoltages appearing in high-voltage networks are considered. It is shown that under these conditions the overvoltages in the elements of the tuning unit can be impermissibly high and exceed considerably the protective level of the protection device mounted on the side of the line taps of the stopper circuit. These data are proved by measurements on stopper circuit prototypes. It is inferred that the requirements to the insulation of the tuning unit of the stopper and to the electric strength of its elements (the inductances and the load resistance) should be more stringent and based on their maximum voltage under possible transient processes rather than on the earlier used voltage of the protective level of the protection device mounted on the side of the line taps of the stopper.     

雷电过电压仿真中非线性元件的建模(英文)

The paper presents some problems of lightning overvoltage modeling in transmission lines with nonlinear elements.The presented results were obtained mostly for fast front transients of subsequent lightning return stroke currents.The effectiveness of numerical algorithms of nonlinear models and possibilities of their development for such transients are analyzed.Computer simulations carried out by application of EMTP show that nonlinear models of back-flashover and ZnO arresters work properly,while the implemented corona model can not be used for relatively large peak values of subsequent lightning return-stroke currents.