Measurement and Characteristic Analysis of Transient Radiated Switching E-Field of GIS

S62 operations inside the gas-insulated substations (GIS) can stimulate transient radiated electromagnetic fields in the space, which can cause great damages to power equipment, especially for secondary device. Therefore, it's of vital importance to investigate the regularities of such switching electromagnetic fields and master their main characteristics. Above all, this paper presents the design of the measurement system of the transient radiated switching E-fields of GIS. Then, many on-site experiments were conducted, based on which the test results were analyzed separately in time domain, frequency domain, as well as joint time-frequency domain. At the end, some key parameters such as the amplitude, the rise time, the dominant oscillation frequency, and the damping factor are extracted as characteristic parameters of transient radiated switching E-fields, and their influential elements such as the switch type, the GIS voltage level and the measurement position are analyzed in detail. In general, this research work aims to grasp the main properties of radiated switching transients of GIS, which can be referential regarding the relevant domains.

I. Introduction

Compared with traditional air insulated substations, GIS has many advantages such as small floor area, long maintenance cycle and isolation from surroundings, etc. Switching operations of the circuit breaker and the disconnecting switch could generate VFTO signals. During the propagation progress of VFTO, when it encounters points of discontinuous impedance such as the GIS shell and outer lead interface, due to the wave reflection and refraction, transient current could appear on the shell and outer leads then strong transient electromagnetic fields could be stimulated in the space^[1]–[5].