Influence of disconnecting part on propagation properties of PD-induced electromagnetic wave in model gis

Abstract

Partial discharge (PD) detection using a UHF (ultra high frequency) band signal is a well known advanced insulation diagnosis method in gas insulated switchgear (GIS), and has been actively studied. Detailed investigation of electromagnetic (EM) wave propagation inside the GIS tank is required for significant improvement of detecting PD signal by UHF method. When practically applying the UHF method to GIS insulation diagnostics, it is necessary to examine the effects of GIS components such as circuit breakers, isolators and disconnectors on EM wave propagation properties. In this paper, attention is paid to the effects of a disconnecting part of a high voltage (HV) conductor like a circuit breaker or a disconnector in GIS.To examine the effects of disconnecting part, the gap length of the disconnecting part was set as parameter, and waveforms and frequency spectra of the propagation PD-induced EM wave were measured with UHF sensors. For the purpose of discussing the effects of the disconnecting part theoretically, a finite difference time domain (FD-TD) simulation was also carried out. The experimental results show that the PD-induced wave could propagate through the disconnecting part with higher frequency components over the cutoff frequency components of TE11 mode for disconnecting part, i.e. cylindrical shape formed by GIS tank without HV conductor. The propagation of the lower frequency components below the TE11 mode depended on the gap length of the disconnecting part.Index Terms -Gas insulated switchgear (GIS), partial discharge (PD), electromagnetic (EM) wave, UHF (ultra high frequency) method, TE11 mode, cutoff frequency, insulation diagnosis, disconnecting part, finite difference time domain (FD-TD).

Effect of excitation current waveform on PD induced electromagnetic wave propagation and attenuation in straight 154 kV GIS model tank with epoxy spacers

“…Experimental setup and procedure are same as before [1][2][3][4][5][6].Figure1 shows the configuration of the experimental setup. Three sensors of UHF-A, UHF-B, and UHF-C have been installed with insulating spacers of the metal flange type.…”

“…In recent years, diagnosis of the electrical insulation of electric power apparatus such as gas-insulated switches (GIS) and transformers by UHF method for detecting partial discharges (PD) has been widely examined [1][2][3][4]. The UHF method allows detection of radiated electromagnetic (EM) waves in UHF band caused with partial PD.…”

Finite‐difference time‐domain simulation of partial discharges in a gas insulated switchgear

“…Several PD detection methods have been proposed so far [1]. Also, numerical simulations using the three-dimensional (3D) finite-difference time-domain (FDTD) method [2] have been carried out [3][4][5]. In [3], the attenuation characteristics of PD-generated electric field in ultra-high-frequency (UHF) band within a single-phase GIS tank have been studied, and the FDTD-computed results have been compared with the corresponding measured ones.…”

“…A PD was generated by a 30 mm long metallic needle attached to the surface of the upper high-voltage conductor, to which a 45 kV AC voltage was applied. Note that a metallic needle of length 10, 15, and 30 mm was used in experiments of [3][4][5], respectively. A PD would emanate and extend from the top of the 30 mm long metallic needle.…”

Simulation and measurement of PD-induced electromagnetic wave leakage in GIS with metal belt

“…The characteristics of the amplitude and frequency of the PD signals were expediently studied by Wang et al [2]. Kaneko et al [3] and Okabe et al [4] have studied respectively the electromagnetic wave radiated from an insulating spacer in GIS and the propagation characteristics of electromagnetic wave in three-phase tank. They found that the aperture between two adjacent bolts is theoretically equivalent to a dipole excited by the leaked electromagnetic waves.…”