Effects of electron migration and adsorption on the suppression of negative corona discharge in nanoparticle transformer oil: experiments and simulations

Abstract

SiO2 and TiO2 nanofluids (NFs for short) were prepared, and a series of DC corona discharge tests were carried out under needle-plate electrode on both NFs and base oil, using the luminous area and pulse current to characterize the negative corona discharge characteristics. The trap distribution characteristic as well as the mobilities of positive and negative ions of the two types of NFs and base oil were measured. A kind of new corona discharge simulation model was established, and the effects of shallow traps and electrons adsorbed by nanoparticles were considered in the simulation model. The corona discharge was simulated under the needle-plate electrode and the simulation results were compared with the corona discharge characteristics obtained from the tests. Furthermore, the effects of shallow trap and electron adsorbed by nanoparticles on space charge and electric field distribution as well as field ionization in transformer oil were analyzed respectively, revealing the mechanism that nanoparticles regulate the carrier migration process to suppress the negative corona discharge of transformer oil.

Electric partial discharges in biodegradable oil-based ferrofluids: A study on effects of magnetic field and nanoparticle concentration

“…It has been shown that the field ionization is the main source of electrons and positive ions in transformer oil [ 32 ], and it can be expressed as follows where q is the elementary charge, is the density of ionizable oil molecules, a is the molecular separation distance, is the electric field intensity, h is Planck's constant, m is the free electron mass, and denotes different ionization potentials. Once the charges are generated, the subsequent electron avalanche and space charge distribution depend on the mobility of charge carriers, including electrons and positive and negative ions [ 33 ]. It is clear that the charge mobility will be further influenced by the dispersed nanoparticles in the oil.…”

Fast Degradable and Thermally Conductive Silicone Rubber Vitrimer with Low Dielectric and UV‐Shielding Properties

“…With the high integration, high power, miniaturization, and portability of electronics, the heat accumulation within the devices becomes more and more serious, which inevitably affects their stability, reliability, and service life. [ 1–4 ] To alleviate the problem of heat accumulation in electronic devices, cooling is typically required. The most common cooling method involves utilizing a heat sink made from highly thermally conductive materials such as copper or aluminum, which is in direct contact with the heat source so as to dissipate the heat to the surroundings.…”