Light Emission Spectrum Depending on Propagation of Partial Discharge in SF<inf>6</inf>

Abstract

An understanding of mechanism of Partial Discharge (PD) in SF6 gas is critical for diagnosis of PD in electric power equipment. Moreover, analysis of PD mechanism contributes to the optimization of the design of electric power applications. For these reasons, we study in detail about PD mechanism by measuring light emission spectrum of PD in SF6 gas.In this paper, under an application of lightning impulse voltage in needle-plane electrodes, we have measured light emission spectrum of leader discharge. As the result, we have found out the light emission of long wavelength above 560nm in leader discharge, and the light emission above 560nm is emitted in the streamer head generated at the tip of the leader channel and radiated from dissociation products depending on the step propagation of leader discharge.These results suggest that we can diagnose the PD propagation in SF6 gas and estimate the risk of breakdown (BD) by measuring PD light emission spectrum in electric power equipment. There are possibilities to contribute to enhance performance of the diagnosis technique in gas insulated power equipment.

Diffuse discharges in SF 6 and mixtures of SF 6 with H 2 , formed by nanosecond voltage pulses in non‐uniform electric field

“…With nitrogen content of 0.5% or more, the bands of the second positive nitrogen system dominated in the emission spectra. Similar line spectra were observed in [22] when investigating the glow of streamer heads and streamer channels in SF 6 gas in a pin‐plane geometry. In this work, after the gap was closed by a channel and the discharge current increased, bands of continuous spectrum appeared in the discharge plasma emission.…”

Statistical Analysis of Partial Discharges in SF6 Gas via Optical Detection in Various Spectral Ranges

“…The spark discharges driven by different mechanisms from the faint corona resulted in more complex spectral lines in the range of 600-695 nm. This result has also been reported in the literature [15] The PDs triggered by the floating particle exhibit two phases with increase in applied voltage. At relatively low applied voltages, the PDs initially occur along the side of the floating electrode that is closer to the upper electrode.…”

“…The spark discharges driven by different mechanisms from the faint corona resulted in more complex spectral lines in the range of 600-695 nm. This result has also been reported in the literature [15] via rapid spectrum measurement. The result has been attributed to light emission originating from certain dissociation reactions involving fluorine based on the assumption that the electrons involved in streamer-like discharges may have obtained energies above 14 eV to excite fluorine.…”

“…For PDs occurring in SF 6 -gas-insulated systems, light is produced as a result of various ionization, excitation, and recombination processes occurring during corona in SF 6 with its characteristic spectrum. Though corona discharge in pure SF 6 occurs over a narrow spectral range due to the small excitation cross-section [14], it can be still detected over a wide EM spectrum from the ultraviolet (UV) to the near-infrared (NIR) ranges depending upon the discharge energy [15]. The presence of trace amounts of impurities, such as air and nitrogen, and the structural nature of the electrode can yield more complex spectra [16,17].…”

Optical sensing in condition monitoring of gas insulated apparatus: a review

“…In addition, many other researchers have used vacuum PMTs for PD detection in SF 6 [39][40][41][42]. And these PMTs were all highly sensitive to PD signals.…”