In-depth understanding of the pollution problems such as dry bands and the polymeric aging process requires better determination of electric field strength and its distribution over the polymeric surface. To determine the electric field distribution over the insulator surface, this research proposes utilizing a novel approach model based on nonlinear electrical characteristics derived from experimental results for polluted polymer insulators. A case study was carried out for a typical 11 kV polymeric insulator to underline the merits of this new modeling approach. The developments of the proposed pollution model and the subsequent computational works are described in detail. The study is divided into two main stages; laboratory measurements and computer simulations. In the first stage, layer conductance tests were carried out to develop nonlinear field-dependent conductivity for the pollution modeling. In the second part, equipotential and electric field distributions along the leakage were computed using the finite element method (FEM). Comparative field studies showed that the simulation using the proposed dynamic pollution model results in more detailed and realistic field profiles around insulators. This may be useful to predict the formation of dry bands and the initiation of electrical discharges on the polymeric surface.

Electrical grounding is an indispensable part of the power system network. The grounding system is mainly affected by grounding resistance and the nature of the soil. High ground resistance produces the phenomenon of soil ionization, surface arching, and back flashover. A conventional grounding system requires the deep digging of electrodes, thus creating maintenance difficulties. This research work focuses on the safe operation of an electric power system from external and internal impulses arising due to lightning strikes or short circuits. The study proposes an application of mineral samples as grounding materials, and bentonite is used as backfilling material in portable grounding systems. A detailed experimental analysis was conducted under controlled conditions to evaluate the performance of selected materials in high-resistance soil. The problem of a deeply driven electrode is addressed by designing the portable grounding system. The study results demonstrate that the proposed portable grounding system could be installed in troubled environments such as forests, deserts, and rocky terrains. To measure the breakdown voltages of the proposed samples, X-ray Diffraction (XRD) analysis and other laboratory tests were conducted. The electric field intensities are extracted through Finite Element Analysis (FEA). The experimental and simulation findings show the expected performance of mineral samples under various operating conditions. The findings of this study can guide the practitioners for safe and efficient operations of portable electrical grounding systems.

The most frequent and dangerous hazard to the electrical insulation of high voltage (HV) and high field (HF) equipment is partial discharges (PD). The development of PD activity is both a cause and an indicator of insulation degradation, which could ultimately lead to insulation breakdown. For electrical power equipment to operate safely and dependably, continuous and efficient PD monitoring must be conveniently performed to prevent associated damages and any harm to electrical power equipment. This work presents the design of a new UHF antenna for detecting PD in medium-voltage gas-insulated applications. The working frequency band of the proposed UHF antenna is 370 MHz–1300 MHz, which translates into a total bandwidth of 930 MHz UHF frequency band. Over the whole operating frequency of the antenna, the return loss is less than -10dB. Recently, an eco-friendly insulating gas, HFO1336mzz(E), is considered to be a good substitute for sulfur hexafluoride (SF6) in medium-voltage gas-insulated equipment (MV-GIE). The HFO(E) gas in a mixture with CO2 can reach the dielectric strength of SF6 gas. Hence, the HFO(E)/CO2 gas mixture’s partial discharge properties are systematically investigated in this research work. In particular, a detailed examination focuses on the partial discharge extinction voltage (PDEV) and partial discharge inception voltage (PDIV) under varying electric field conditions at different gas pressure levels and mixing ratios. The PDIV of the HFO(E)/CO2 gas mixture exhibited a linear-saturation rising pattern with both mixing ratio and gas pressure, mirroring the trend observed in SF6 when the HFO(E) gas concentration ranged between 25% and 30%.

Gas-insulated systems are widely utilized in the electric power sector to transmit and distribute electrical energy. Sulphur-hexafluoride (SF ₆ ) has dominated gas insulation in high-voltage insulation technology since the early 60s. It is a greenhouse gas with a protracted lifespan in the atmosphere. This paper proposes an economical and comparatively more environmentally friendly R507 gas alternative to SF ₆ for medium-voltage applications. R507 has been analyzed experimentally through power frequency breakdown and lightning impulse testing to validate the performance and theoretical concepts. R507 has a very low liquefication temperature of -46.7°C, but it must still be mixed with buffer gases such as CO ₂ , N ₂ , or dry air to meet the diverse liquefaction temperature applications. Various field utilization factors under AC and lightning impulse voltages are used in the experiments, along with different electrode geometries, including sphere-to-plane and rod-to-plane (i.e., quasi-homogeneous and inhomogeneous electric field distribution). For comparison, identical experiments are conducted with pure SF ₆ . R507 gas was found to be a promising substitute for SF ₆ gas, with its dielectric strength being approximately 0.95 times that of SF ₆ gas. A positive synergistic effect is present between R507 and CO ₂ , along with the good self-recoverability property of the gas mixture. The current research study serves as a fundamental resource for characterizing the R507/CO ₂ gas mixture insulation properties to be utilized in practical applications.

This paper investigates C₄H₂F₆, a promising environmentally friendly insulating gas that possesses high dielectric strength and a low global warming potential. The study focuses on examining the insulation properties of C₄H₂F₆ when combined with CO₂/N₂, aiming to assess its suitability as a substitute for SF₆ in gas-insulated applications. Finite element analyses are performed to evaluate the field utilization factor and electric field distribution in the proposed mixture. The properties of liquefaction temperature were examined in this study to determine the optimal mixing ratio for applications that require a minimum working temperature. Extensive experimental investigations were carried out to assess the dielectric strength characteristics of the gas mixture in both uniform and quasi-uniform electric fields. It was found that pure HFO-1336mzz (E) exhibits a dielectric strength approximately 1.2–1.6 times higher than SF₆. Experimental results have revealed that the insulation performance of a 30% HFO-1336mzz (E)/CO₂ mixture closely resembles that of SF₆, with a matching efficiency of up to 90% in a weakly uniform electric field. This remarkable performance can be attributed to a positive synergistic effect between HFO-1336mzz (E) and CO₂, combined with the gas mixture’s excellent self-recoverability property. These experimental findings are further supported by finite element analysis, which confirms the observed results. The 30% HFO-1336mzz (E)/CO₂ gas mixture at 0.15–0.20 MPa pressure and constant 0.6 mm air gap reveal superior insulation tolerance and less sensitivity to the electric field, confirming its promising medium-voltage engineering applications. The associated results of this research provide a critical reference for the engineering application of the alternating (AC) and direct current (DC) insulation characteristics of the HFO-1336mzz (E)/CO₂ gas mixture.