Correlation Characteristics Comparison of SF6 Decomposition versus Gas Pressure under Negative DC Partial Discharge Initiated by Two Typical Defects

Abstract

Aimed to clarify the correlation characteristics between the internal partial discharge (PD) in negative direct current (DC) gas insulated system (GIS) and gas pressure initiated by two typical defects (i.e., free-metal particles and metal protrusion), this study on PD decomposition of sulfur hexafluoride (SF 6 ) was investigated under different pressures on the basis of constructing a SF 6 decomposition experimental platform with DC PD. Free-metal particles and metal protrusion in a GIS were simulated using a spherical-bowl electrode and a needle-plate electrode, respectively. Trends and differences in the performance of SF 6 decomposition components SOF 2 , SO 2 F 2 , CO 2, and SO 2 at different pressures were compared and analyzed by experiments under different defects. Based on gas microscopic ionization theory, the relationship between the decomposition component and gas pressure was deduced and verified. The concentrations of different decomposition components were found to vary with the change in gas pressure under different defects, whereas the characteristic ratios of decomposition components versus gas pressure showed a similar trend.

An Investigation of Negative DC Partial Discharge Decomposition of SF6 Under Different Metal Materials

“…The needle and plate electrodes were made of Cu, Al, and 304 stainless steel, which are common in DC gas-insulated equipment. Because the laboratory equipment pressure generally ranges from 0.10 to 0.40 MPa [23] and to ensure the comparability of experimental data, gas chamber pressure (absolute pressure), ambient temperature, and relative humidity were constant (0.35 MPa, 25 • C, and 50%, respectively) Water vapor content was less than 10 µL/L, and oxygen content was less than 100 µL/L. The SF 6 decomposition products were measured by Shimadzu GC-2010 Pro gas chromatograph (GC) (99.999% purity helium gas was used as carrier gas, with a flow rate of 2 mL/min, column temperature of 40 • C, injection volume of 1 mL, and diversion ratio of 10:1).…”

Study of spatial and temporal evolution of Ar and F atoms in SF6/Ar microsecond pulsed discharge by optical emission spectroscopy

“…In this paper, the PD caused by metal protrusion defects was simulated by a needle-plate electrode, which is encountered at the forefront of insulation defects from the point of triggering GIS failure rates [24]. The discharge was powered by pulsed high voltage [25] in SF 6 /Ar gas mixtures.…”

Failure Prognosis of High Voltage Circuit Breakers with Temporal Latent Dirichlet Allocation

“…Degradation of the HVCB is caused by several types of stress and aging, such as mechanical maladjustment, switching arcs erosion, and insulation level decline. The existing literature covers a wide range of specific countermeasures, including mechanism dynamic features [8][9][10], dynamic contact resistance [11], partial discharge signal [12,13], decomposition gas [14], vibration [15], and spectroscopic monitoring [16]. Furthermore, numerous studies applied neural networks [8], support vector machine (SVM) [17], fuzzy logic [18], and other methods [19], to introduce more automation and intelligence into the signal analysis.…”

“…The final average output reflects the time decrease presented in Equation (16) due to the multi-sampling process. Finally, Equation (14) provides the future distribution prognosis using the learned parameters of the last sub-sequence of each HVCB. Initialization: randomly assign failure patterns and make sub-sequences by ; 2:…”