Surface Discharges and Flashover Modelling of Solid Insulators in Gases

Slama, Mohammed El Amine; Béroual, Abderrahmane; Haddad, A.

doi:10.3390/en13030591

Cited by 6 publications

(8 citation statements)

References 24 publications

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“…The polarity of flashover for all used insulators is identical to breakdown in gas gap alone independent of the gas type, except for the Epoxy insulator. Based on this observation, it can be said that the gas pressure plays an important role on the discharge propagation causing the discharge to stick to the insulator surface as the pressure increases as observed by [33,34]. It was found that, depending on the polarity, the efficiency of the charge injection from the solid insulator or the attachment/recombination process will govern the propagation path.…”

Section: Surface Discharge and Flashover With Solid Insulatormentioning

confidence: 95%

“…This results in a reduction of the surface flashover voltage. On the other hand, it was observed that the surface discharge trends to stick the insulator surface with the increasing of the gas pressure [33,34,37,38]. This can explain the relative stability of the surface flashover voltage for high pressures: the main electrical charges are collected from insulator caused by the increase of the attachment process with the gas pressure rising.…”

Section: Surface Discharge and Flashover With Solid Insulatormentioning

confidence: 99%

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AC Volume Breakdown and Surface Flashover of a 4% NovecTM 4710/96% CO2 Gas Mixture Compared to CO2 in Highly Nonhomogeneous Fields

et al. 2020

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AC pre-discharge currents, breakdown, and flashover voltage measurements are reported in a 10 mm needle-plane arrangement in a 4% NovecTM 4710/96% CO2 gas mixture and compared with CO2 for pressures up to 8.8 bar abs. Flashover measurements were performed on different solid dielectrics (Al2O3_filled epoxy resins, PTFE (Polytetrafluoroethylene) and PE (polyethylene)) for different roughness surface finishes. The effect of fixed conducting needles at various positions on electrical strength is reported. A strong nonlinear behaviour as function of gas pressure was observed for all the studied parameters (gas, needle position, solid insulator, insulator roughness). The non-linear behaviour is attributed to the inception and quenching of glow corona, in the interval between inception and breakdown or flashover voltages. It is found that a 4% concentration of NovecTM 4710 in CO2 has a breakdown/flashover voltage ≈ 1.14 higher than CO2. The glow corona-induced stabilization effect is seen for pressures between 2 and 5 bar abs for all the studied parameters. The peak flashover voltage and its associated pressure of the different insulators are strongly dependent on surface roughness. At 8.8 bar abs, the flashover voltage level obtained with various materials was ordered as follows: PTFE > PE-UHMW > Epoxy > HDPE(High-density polyethylene).

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Section: Surface Discharge and Flashover With Solid Insulatormentioning

confidence: 95%

Section: Surface Discharge and Flashover With Solid Insulatormentioning

confidence: 99%

AC Volume Breakdown and Surface Flashover of a 4% NovecTM 4710/96% CO2 Gas Mixture Compared to CO2 in Highly Nonhomogeneous Fields

et al. 2020

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“…Knowledge of dielectric breakdown of a gas insulated system requires modelling the basic precursors, such as the streamer inception, streamer propagation, and the streamer to leader transition. With the latter appearing when the streamer discharge reaches a certain length [20]. From the engineering point of view, it is important to highlight geometrical features suffering from excessive electrical stress in order to optimize their shape.…”

Section: Streamer Breakdownmentioning

confidence: 99%

“…When dealing with electrode-insulator systems, the flashover voltage, corresponding to occurrence of the electric discharge between the electrodes, can be estimated using empirical relations or analytical formulas derived from a circuit model [20].…”

Section: Streamer Breakdownmentioning

confidence: 99%

Automatic Optimization of Gas Insulated Components Based on the Streamer Inception Criterion

2021

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Gas insulated transmission lines (GILs) are used in electrical systems mainly for power transmission and High Voltage substation interconnection. In this paper, we focus on the development of complex numerical tools for the optimization of gas insulated HVDC components by the estimation of realistic electric field distribution and the voltage holding of the designed geometry. In particular, the paper aims at describing the correct modelling approach suitable to study high voltage components in DC, considering the nonlinear behaviour characterizing the electrical conductivity of solid and gas insulators. The simulated field distribution is then adopted to estimate the voltage holding of the dielectric gas, with a convenient engineering technique, based on the streamer criterion. These two tools are integrated in an automatic optimization package developed in COMSOL® and MATLAB®, with the purpose of adjusting the critical geometry features, suffering from excessive electrical stress and possibly giving rise to electrical breakdown, in order to guide the designer towards a robust solution.

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“…Even if ITs are not the most critical asset of the grid, such as cable joints [4][5][6] and insulators may be [7][8][9], studies on them are always clear and current. As a matter of fact, the IT is a key element that provides information on what is happening to the power network in every single instant.…”

Section: Introductionmentioning

confidence: 99%

Smart Characterization of Rogowski Coils by Using a Synthetized Signal

Mingotti

Peretto

Tinarelli

2020

Sensors

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With the spread of new Low-Power Instrument Transformers (LPITs), it is fundamental to provide models and characterization procedures to estimate and even predict the LPITs’ behavior. In fact, distribution system operators and designers of network models are looking for all forms of information which may help the management and the control of power networks. For this purpose, the paper wants to contribute to the scientific community presenting a smart characterization procedure which easily provides sufficient information to predict the output signal of a Low-Power Current Transformer (LPCT), the Rogowski coil. The presented procedure is based on a synthetized signal applied to the Rogowski coil. Afterwards, the validity of the procedure is assessed within the Matlab environment and then by applying it on three off-the-shelf Rogowski coils. Simulations and experimental tests and results involving a variety of distorted signals in the power quality frequency range and by adopting a quite simple measurement setup demonstrated the effectiveness and the capability of the procedure to correctly estimate the output of the tested device.

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Surface Discharges and Flashover Modelling of Solid Insulators in Gases

Cited by 6 publications

References 24 publications

AC Volume Breakdown and Surface Flashover of a 4% NovecTM 4710/96% CO2 Gas Mixture Compared to CO2 in Highly Nonhomogeneous Fields

AC Volume Breakdown and Surface Flashover of a 4% NovecTM 4710/96% CO2 Gas Mixture Compared to CO2 in Highly Nonhomogeneous Fields

Automatic Optimization of Gas Insulated Components Based on the Streamer Inception Criterion

Smart Characterization of Rogowski Coils by Using a Synthetized Signal

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