气体绝缘变电站母线结构参数对外壳暂态过电压影响分析

The Influence of Gas Insulated Substation Structural Parameters on Transient Enclosure Voltage Waveform

母线结构参数和等效模型的确定是分析气体绝缘变电站(GIS)母线系统外壳暂态电压(TEV)的基础。应用分离元法(PSEC)确定分箱式母线系统阻抗参数,根据传输线理论得到单相GIS母线系统集中参数简化计算模型。同时,采用数学解析方法分析了GIS外壳暂态过电压影响因素。并对不同母线结构下TEV进行仿真,得到其电压波形及幅频特性曲线,验证了简化模型的可行性。在此基础上,讨论电弧电阻、断路器断口电容、末节母线长度、接地线波阻抗及数量等结构参数对TEV峰值的影响。仿真结果表明,TEV是由多个频率分量组成的电压波,其峰值与母线末端电压基本成比例关系,电弧电阻可以延迟TEV出现的时间,降低断路器断口电容与接地线波阻抗,增加末节母线长度和接地线数量能降低TEV峰值。

Structural parameters and equivalent model of the bus-bar system are the foundations for analyzing transient enclosure voltage （TEV） of gas insulated substation （GIS）. In this paper, partial sub-conductor equivalent circuit （PSEC） is applied to calculate the impedance parameters of the insulated-phase bus-bar system, and the theory of transmission line in single-phase GIS bus-bar system is used to establish the simplified mode with lumped parameters. Meanwhile, mathematical analysis method is used to analyze the factors affecting transient over-voltage of GIS enclosure. The TEV is simulated under different configurations, and then the voltage waveform graph and amplitude- frequency characteristic curve are acquired, which verify the simplified model. On this basis, the effects on the peak value of TEV are discussed, including the fracture capacitance of circuit breaker, the length of the last bus-bar section, and the impedance and number of earth wire. The simulation results show that TEV is a type of voltage wave composed by multiple frequency components, and its peak is proportional to the bus bar terminal voltage. TEV occurrence time can be delayed by the arc resistance, and the peak value of TEV can be decreased by reducing fracture capacitance of the circuit breaker and impedance of earth wire, and increasing the length of the last bus-bar section and the quantity of earth wire.