Propagation Characteristics Analysis of Fault Transient Voltage Traveling Wave in GIL Considering External Connection

This paper untangles a typical application scenarios of gas-insulated transmission line (GIL) and establishes simulation models respectively. By simulating the grounding fault, the propagation characteristics of transient traveling wave in GIL and the influence of external connection equipment on traveling wave characteristics are analyzed. Through the simulation, it is found that the reflection of transient traveling wave process is obvious due to the larger wave impedance of overhead lines, which is conducive to fault location. The wave impedance of the cable becomes smaller and the negative reflection is smaller, but there are still obvious reflection characteristic moments, which can be used for location. The impedance change between gas-insulated switchgear (GIS) and GIL is very small, and there is no obvious reflection characteristic moment, which will seriously affect the fault location. Due to the influence of port capacitance, the transient traveling wave of transformer is distorted obviously, but there is still obvious reflection time, which is helpful to fault location. This paper analyzes the propagation characteristics of GIL fault transient traveling wave in different application scenarios, which provides theoretical support for the realization of single-terminal fault location, and is helpful for the selection of location measure point and the calculation of characteristic moment in practical application.