Research on Simulation Technology of Transient Electromagnetic Disturbance in Miniature GIS

The Gas Insulated Substation (GIS) has a compact structure and short electrical distance. During disconnector operations, switch arcs produce very fast transient overvoltages (VFTO) that propagate as waves. These waves reflect at impedance changes, causing overvoltages up to 3.0 per unit, with wavefront times in nanoseconds and frequencies up to 100 MHz. Switching can produce dozens of transient processes. VFTO can cause GIS insulator discharges, transformer insulation damage, and system malfunctions, making them severe electromagnetic transients. Due to the complex nature of VFTO and GIS structures, accurate mathematical modeling is challenging. Experimental research on VFTO distribution characteristics is urgently needed. This paper proposes a miniature GIS transient electromagnetic disturbance simulation technology. A 50:1 scale test device for 330kV GIS power equipment includes a nanosecond pulse source, a 20m coaxial GIS simulation pipeline, switches, and measurement ports. The device can be configured into various structures, such as 'I', 'h', and 'H'. By injecting nanosecond voltage pulses, the intensity distribution and waveform changes of transient overvoltages are studied, enabling accurate analysis of GIS transient disturbances in actual power systems.