Investigating optimal region for thermal and electrical properties of epoxy nanocomposites under high frequencies and temperatures

Abstract

This research investigates the optimal region to achieve balanced thermal and electrical insulation properties of epoxy (EP) under high frequency (HF) and high temperature (HT) via integration of surface-modified hexagonal boron nitride (h-BN) nanoparticles. The effects of nanoparticle content and high temperature on various electrical (DC, AC, and high frequency) and thermal properties of EP are investigated. It is found that the nano h-BN addition enhances thermal performance and weakens electrical insulation properties. On the other side, under HF and HT stress, the presence of h-BN nanoparticles significantly improves the electrical performance of BN/EP nanocomposites. The EP has superior insulation properties at low temperature and low frequency, whereas the BN/EP nanocomposites exhibit better insulation performance than EP under HF and HT. The factors such as homogeneous nanoparticle dispersion in EP, enhanced thermal conductivity, nanoparticle surface modification, weight percent of nanoparticles, the mismatch between the relative permittivity of EP and nano h-BN, and the presence of voids in nanocomposites play the crucial role. The optimal nanoparticle content and homogenous dispersion can produce suitable EP composites for the high frequency and high temperature environment, particularly solid-state transformer applications.

Large‐scale plasma grafts voltage stabilizer on hexagonal boron nitride for improving electrical insulation and thermal conductivity of epoxy composite

“…Furthermore, as shown in the XRD pattern in Figure 3c, the results before and after grafting both contain (002), (100), (101), (102), and (004) crystal plane (2 θ = 26.78°, 41.65°, 43.93°, and 50.19°, respectively) corresponding to hBN. In the case of surface‐modified nano hBN, the same suppressed XRD peaks than raw hBN are observed, which may be attributed to the exfoliation of pristine hBN by successful grafting [42]. Obviously, the (002) crystal plane is absolutely dominant here, so the computational chemistry model in the following paper mainly studied this crystal plane of hBN.…”

Influence of dielectric barrier effect and thermally‐conductive network on thermal and electrical properties of epoxy under different frequencies and temperatures

“…Figure 6 describes the variation of dielectric loss (tan δ ) at different frequencies and temperatures. For the reliable operation of dielectric insulation, it should have minimum dielectric loss 37 . Figure 6a explains that all the EPR micro‐nano composites initially exhibit higher tan δ values than EPR at 25°C and at frequency < 1 kHz.…”

“…For the reliable operation of dielectric insulation, it should have minimum dielectric loss. 37 Figure 6a explains that all the EPR micro-nano composites initially exhibit higher tan δ values than EPR at 25 C and at frequency < 1 kHz. However, above 1 kHz, the EPR suffers from the highest tan δ among all the samples (except M5N0 ≈ EPR).…”

Multi‐modified epoxy insulation with improved flashover threshold for HVDC applications

“…It is commonly accepted that renewable energy sources prefer direct current (DC) over alternating current due to its large volume and elongated transmission, small footmarks, storage abilities and smart use of electricity. In recent decades, epoxy has emerged as an important insulation candidate and has been used in various applications of DC systems, such as Gas-insulated switchgear, electronic packaging, power inverters and in high-frequency power transformers [2,3]. However, there are several challenges and drawbacks in using epoxy in such systems that need to be resolved for the reliability and safety of the power system.…”