两级雷击电涌保护器配合的过电流和过电压变化特征

通过对电气系统受两级雷击电涌保护器（surge protective divice，SPD）配合保护下的过电流和过电压变化特性的分析研究，建立过电压两级保护线路的瞬态Kirchhoff方程组，对各SPD、级间电缆（或解耦器）和负载的端电压、电流进行模拟计算，绘制时序波形图，获得两级SPD（首级为火花间隙、次级为压敏电阻）配合保护下的雷击过电流的分流特性和负载过电压变化特性，为雷击过电压过电流的多级保护提供理论分析方法，可供电气系统多级雷电防护工程设计参考。

Characteristics of Overcurrents and Overvoltages in Electrical System Protected by Coordinated Two-Stage Lightning Surge Protective Devices

The characteristics of overcurrents （OC） and overvoltages （OV） in electrical system protected by coordinated two-stage lightning surge protective devices （SPD） （the first is a spark gap, the second is a metal oxide varistor） were researched and transient Kirchhoff equations of OV protected by two-step circuits were built. The OC and OV of every SPD, conducting cables between SPDs（ or decoupling devices） and loads were calculated and simulated. Waveforms of initial lightning surge, distributing currents in every SPD and load and load voltage varying with time were obtained according to the equations. Therefore, the features of OV on load and OC distributed in the circuit, Which were protected by coordinated two-stage SPD, were concluded. The results are advisable to provide a theoretical method for the multi-stage protection against lightning surge current, and also can be reference for the design of lightning protection engineering in electrical system.