Temperature and Field Induced Variations of Electric Conductivities of HTV Silicone Rubbers Derived from Measured Currents and Surface Potential Decay Characteristics

Alam, Shahid; Serdyuk, Yuriy V.; Gubanski, Stanislaw

doi:10.3390/en13112982

Cited by 8 publications

(1 citation statement)

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“…[29] Based on these findings, it is conjectured that by exposing the studied samples to corona discharge, the threshold E reduces significantly, and thereby charge injection at metal-material interface becomes prominent giving rise to more space charge effect, particularly at high temperatures. On the other hand, for the unaged samples, this range of E is observed as much lower for producing such effects as is also reported in Alm et al [31]…”

Section: Parametersupporting

confidence: 74%

Corona‐aged performance of nano‐filled HTV silicone rubber

Saleem

Akbar

Alam

2022

Plasma Processes & Polymers

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To develop compact and relatively low maintenance demanding high voltage transmission systems, polymeric insulators are widely replacing traditionally used insulators for the past several decades. Further efforts focusing on enhancing their antiaging performance by adding fillers to increase the reliability of power systems are being made through extensive research globally. Among the causes of degradation, corona discharge is considered of great concern and needs to be investigated at length. Toward that end, several types of high‐temperature vulcanized silicone rubber (HTV‐SiR) were reinforced with varying quantities of nano‐sized boron nitride (BN) and silicon carbide (SiC) fillers are evaluated in this study. Test samples with different formulations are fabricated and exposed to alternating current (AC) corona discharge for a duration of 72 h. Thereafter, the induced modifications in their surface characteristics and bulk properties are assessed using several diagnostic and complementary techniques involving measurements of partial discharge and volume current, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. The volume current is recorded using a standardized three‐electrode system at different levels of the test voltage and ambient temperature in an attempt to evaluate its dependence on the electric field and temperature. As a result of the conducted study and allied analysis, it is reported that the damaging impact of corona retards more in the case of loading HTV‐SiR with nano‐sized particles of BN as compared to SiC. The obtained FTIR spectra demonstrate an increase in the transmittance intensity of principal peaks in the aged samples, being higher in the unfilled SiR than its filled counterparts. It is further revealed that exposure of the studied samples to corona discharge elevates their volume current possibly due to charge injection and space charge effect, particularly at higher temperatures and strong electric field.

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Section: Parametersupporting

confidence: 74%

Corona‐aged performance of nano‐filled HTV silicone rubber

Saleem

Akbar

Alam

2022

Plasma Processes & Polymers

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Dielectric relaxation in open circuit: Theory, simulations, and some experiments

Molinié

2023

Journal of Applied Physics

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Static charge on insulating material surfaces may be a source of nuisance and an operational requirement in many devices. It induces a potential that evolves with time due to conduction and polarization processes in the dielectric. Here, we analyze, from a theoretical and experimental point of view, the response of an insulator subjected to a charging pulse, within the frame of linear system theory. The surface potential decay and the return voltage after a brief neutralization, which can be easily measured using an electrostatic probe, usually follow time power laws. We consider here a dielectric following the classical Cole–Cole response function in the frequency domain and derive an exact analytic formula for the potential decay, which involves a Mittag–Leffler function. The relationship between the potential decay and the absorption current when a constant voltage is applied on the dielectric is also analyzed. Experiments on several common insulating materials are analyzed according to this theory, using a numerical simulation with a two-cell model. Return voltage measurements are used to check which materials behave according to the linear model. We underline that an equivalent circuit using constant-phase elements, corresponding to several cells following the Cole–Cole response, can also represent dipolar motions in the dielectric as charge hopping between energy-distributed traps.

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