Onset voltage of a particle-initiated negative corona in a co-axial cylindrical configuration

Ward, Sayed A.; Morsi, R.; Badawi, Mohamed

doi:10.1088/0022-3727/46/4/045205

Cited by 13 publications

(5 citation statements)

References 11 publications

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“…The charge residual coefficient depends on the rate of charge dissipation, namely the rate of charge transfer through the coating to the electrode. The volume current J depends on the electric field strength of the electrode E e and the volume conductivity γ c of the coating, as shown in equation (13). Therefore, the high-voltage electrode should choose the coating with larger volume conductivity to reduce the η, and the ground electrode should choose the coating with smaller volume conductivity to increase the η.…”

Section: ( ) R P P R + >mentioning

confidence: 99%

“…Compared with the motion of particles concentrated in the grounded enclosure under AC voltage, the particles present reciprocal motion between electrodes under DC voltage, especially wire and flaky particles have a special motion-firefly, namely, the particles perform the steering motion without colliding with the enclosure or suspended on the surface of conductor [10,11], as shown in figure 1. The firefly particles move along the conductor and even adsorb on the insulator surface, significantly reducing the gas-solid insulation strength [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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Physical mechanism of electrode coatings to suppress wire particle’s firefly motion under DC stress and selecting criterion for in situ applications

Chang

Geng

et al. 2023

Phys. Scr.

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The Wire metal particles in gas-insulated equipment such as GIS (Gas-Insulated Substation) and GIL (Gas-Insulated transmission lines) under DC stress present a special firefly motion behaviour, namely a long-term levitation on the surface of conductors. However, the electrode coating, as a key device available to suppress the movement of particles, lacks of a theoretical basis as well as an effective selecting criterion to suppress wire particle’s firefly. In this paper, a test platform is established to obtain the charge dynamics and ionic wind characteristics of the wire particles on the coated electrodes. Experimental results illustrate that, the polarity alternation of wire particle charge due to the space charge accumulation near the wire particles as well as the ionic wind generated by the wire particles, is the key impact factor upon firefly motion. The coated electrodes will reduce the surface conduction current and thereby suppress the particle corona discharge, consequently suppressing the firefly motion by limiting the charge acquisition and ionic wind speed of the wire particles. Based on the above research, a selecting criterion of electrode coating material is further proposed. Electrode coatings is primarily expected to increase the corona onset voltage of the wire particles on the coating surface, so as to lower the ionic wind at the end of the particles less than 1m/s. Regarding the high voltage conductor, the coating material with relatively large conductivity is recommended, while for the grounded enclosure, the coating material with smaller conductivity is preferable as to constrain the particles adhere to the enclosure, thereby preventing the firefly motion of wire particle. Both the clarified physical mechanism and the proposed selecting criterion of electrode coating presents theoretical and quantitative guidance for DC GIL design from a specific point of view in suppressing the firefly motion.

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Section: ( ) R P P R + >mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Physical mechanism of electrode coatings to suppress wire particle’s firefly motion under DC stress and selecting criterion for in situ applications

Chang

Geng

et al. 2023

Phys. Scr.

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“…This section presents the breakdown voltage test as an indicator for dielectric severity in power system equipment [36,37]. Two practical transformer oil types of NYTRO 10 XN, and HyVolt III and their 50/50% mixture were evaluated for breakdown voltage.…”

Section: A Breakdown Voltage Testmentioning

confidence: 99%

Reliable Estimation for Health Index of Transformer Oil Based on Novel Combined Predictive Maintenance Techniques

et al. 2022

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“…The reason is that increase of spherical electrode diameter decreases the unevenness of gap electric field in combination with figure 4(b). The unevenness of the electric field can be indicated by the uneven coefficient f, and it is the ratio of maximum field strength E max and average field strength E avg under the unit voltage [25]…”

Section: Impact Of Electrode Sizes On Initial Time Delay Of Streamermentioning

confidence: 99%

Distribution characteristics for initial time delay of streamer of shielding spheres under operating impulse voltage at high altitudes

Geng¹,

Cheng²,

Wang³

et al. 2022

J. Phys. D: Appl. Phys.

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With continuous promotion of construction of UHV DC projects in high-altitude areas, it is of important theoretical and practical engineering significance to study long gap discharge characteristics at high altitudes. As the initial and key stage for development of long air gap discharge, the initial stage of streamer reflects the randomness of long gap discharge to a certain extent, and time delay characteristics are important indicators to reflect the randomness. In this paper, we build a photoelectric detection system based on the photomultiplier tube and photoelectric integrated sensor, carry out an operating impulse discharge test of long gap of the shielding sphere-plate with different diameters at altitudes of 50 m and 2,200 m respectively, obtain the space field strength, optical power, discharge current and voltage of the whole process of discharge development, and analyze the characteristics of boost time delay and statistical time delay of streamer based on the photoionization model and Weibull Distribution model. According to study results, the average value and dispersibility of initial time delay of streamer increase with the increase of altitude and electrode diameter; the boost time delay t0 of streamer decreases with increase of altitude and increases with increase of electrode size; the statistical time delay ts of streamer can properly comply with Weibull distribution, and its characteristic parameter has a clear physical meaning. The dispersibility of statistical time delay will increase with altitude and electrode size, and compared with electrode size, altitude has a greater impact on the dispersibility of statistical time delay. The study results of this paper have important guiding value for selection and optimization on clear distance of the valve hall of a converter station in high altitude areas.

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Onset voltage of a particle-initiated negative corona in a co-axial cylindrical configuration

Cited by 13 publications

References 11 publications

Physical mechanism of electrode coatings to suppress wire particle’s firefly motion under DC stress and selecting criterion for in situ applications

Physical mechanism of electrode coatings to suppress wire particle’s firefly motion under DC stress and selecting criterion for in situ applications

Reliable Estimation for Health Index of Transformer Oil Based on Novel Combined Predictive Maintenance Techniques

Distribution characteristics for initial time delay of streamer of shielding spheres under operating impulse voltage at high altitudes

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