Because of their outstanding electrical, thermal, mechanical, and chemical characteristics, nanofillers, such as zinc oxide (ZnO), have received so much interest in further strengthening composites. The addition of ZnO to a polymer matrix can improve load transmission and composite strength. As a result, by incorporating nanofillers into current polymer systems, composite performance and application range can be enhanced . Because of their intrinsic characteristics, nanofillers are particularly essential in developing polymer nanocomposites. Some NPs (e.g., ZnO) have outstanding stability, a high refractive index, hydrophilicity, ultraviolet (UV) resistance, great transparency to visible light, nontoxicity, strong photocatalytic activity, and low cost. ZnO may be made into various nanostructures, including nanorods, nanowires, spherical NPs, and tetrapods, and is a multifunctional n-type (II–V) semiconductor with a large binding energy (60 meV), excellent UV absorbance, and a broad band gap (3.4 eV) . Because ZnO is nontoxic and environmentally benign, it may be used in bio-applications and is a low cost substance found in conductive glass, white paint, and commercialized sunscreens . ZnO NPs (NPs) have unique properties allowing them to exist in either an anti-electrostatic or conductive state. In the literature, the electrical , magnetic , chemical , and optical  properties of ZnO NPs are remarkable. It has been used in catalysis and semiconductor manufacturing.
The high exciton-binding energy of ZnO would allow for excitonic transitions even at room temperature, which could mean high radiative recombination efficiency for spontaneous emission and a lower threshold voltage for laser emission. The lack of a center of symmetry in wurtzite, combined with a large electromechanical coupling, results in strong piezoelectric and pyroelectric properties and, hence, the use of ZnO in mechanical actuators and piezoelectric sensors [8, 9]. ZnO is a potential candidate for optoelectronic applications in the short wavelength range (i.e., green, blue, and UV), information storage, and sensors as it exhibits properties similar to those of GaN [10–12]. ZnO NPs are promising candidates for various applications, such as nanogenerators , gas sensors , biosensors , solar cells , varistors , photodetectors , photocatalysts , piezoelectric, transducers and light-emitting diodes, various optoelectronic devices, biomedical applications, plant science, and wastewater treatment [20–22]. From a literature review, it was found that various approaches for preparing ZnO nanopowders have been developed, namely, sol-gel, microemulsion, thermal decomposition of organic precursor, spray pyrolysis, electrodeposition, ultrasonic, microwave-assisted techniques, chemical vapor deposition, and hydrothermal and precipitation methods [23–32].
Electron beam (EB) irradiation technique has lately become a sophisticated approach for improving material physical properties like thermal stability, structural, conductivity and mechanical. When EB energy interacts with polymer material, it promotes molecular structural changes like atom displacement, carbonization, ionization, and the generation of free radicals, which aid in chain scission and cross-linking processes. As a result, polymer matrices has become a important research topic in science, especially in industrial applications such cable, wire, electrical devices, marine, and medical. Radiation can only alter the polymer's chemical makeup; however, it can also enhance the presence of trapped charges or produce matrix defects . Physical characteristics are directly affected by this structural change in the irradiated polymer electrolyte; in this case, dielectric permittivity and electrical conductivity improved as the dosage was raised. The above modifications are influenced by the physics and chemistry of the absorbed products, as well as the selected radiation energy and dose as a result of cross-linking or chain scission. The existence of trapping charge within the material was affected by the induced radiation, which increased the transport property. It's also been discovered that altering a polymer's functional group alters the physical characteristics of polymer films. Changes in electrical, dielectric, and thermal characteristics occur as a result of irradiated polymers can be attributed to these changes [34, 35]. In other words, irradiated polymers can be converted from insulators to materials with good electrical conductivity, which is a good sign since these materials can be used in various electronic applications.
Sharshir et al.  have used a melt mixer to prepare cross-linked polyethylene (XLPE) cables composited with copper NPs (CuNPs). Different NP ratios were used to make the XLPE/Cu nanocomposites (i.e., 0, 1, 3, and 5 wt%) at different EB irradiation doses of 0, 15, 20, and 25 kGy. In a frequency range of 50–1.5 MHz, the relative permittivity (εr), dielectric constant (ε΄), dielectric loss factor (ε΄ˊ), and conductivity (tan) were calculated. The improvement in the electric field uniform occurs in the middle of the 25-kGy XLPE/5-ZnO film cable that has a CuNP content of 5 wt% and irradiated at 25 kGy.
Kim et al.  have highlighted in a recent study that the undertaken modifications in the chemical and physical structures of XLPE insulation behavior, under thermal aging, lead to many changes in the dielectric characteristics of XLPE. The mechanical properties of XLPE decreased. From another viewpoint, the leakage current can be considered an important indicator of high-voltage insulation degradation. Moreover, the leakage current can flow through the surface and/or bulk of the materials, and this current can have a solid relation with the aging process. Lei, Weiqun, et al.  have examined the preparation of XLPE/silicon dioxide (SiO2) nanocomposites, which used DC currents. The strength of the nanobreakdown composite was considerably greater than that of the unfilled XLPE in the DC phase test. The difference between the typical lives of the nanocomposite and its empty base polymer dropped when the applied field was reduced, and the lifetimes were relatively similar when the applied field was 130 kV/mm, according to endurance tests.
Here, XLPE/ZnO nanocomposites were thoroughly investigated according to the impact of various contents of ZnO on XLPE polymers, including simulating the electric field distribution. The XLPE/ZnO nanocomposites irradiated with EB were simulated using the COMSOL Multiphysics program. The first part of this study is about the preparation and characterization of ZnO NPs. The second part explains the simulation steps and shows how electric field strength propagates in ZnO NPs filled with XLPE medium-voltage (MV) cables. When ZnO NPs were filled into XLPE, they increased conductivity and decreased permittivity, resulting in a uniform electric field arising from the current flow via MV cables.