Influence of Defect Size on Insulation Deterioration of Epoxy Resins with Voids

Abstract

This study investigates the relationship between void size and insulation lifetime due to partial discharges (PDs) in internal voids. Experimental results clearly show that the larger the void size, the shorter the insulation lifetime, which decreases the lifetime nvalue index of the voltage-time characteristics. The results also show a clear relationship between the insulation lifetime of a solid insulator having void defects and the PD energy generated in the void, which is related to the cumulative PD energy density per cycle. Therefore, we propose estimating the insulation lifetime of an insulator with voids by calculating the cumulative PD energy density per cycle.

Bio-based Tetrafunctional Epoxy Monomer Containing a Dicyclo Diacetal Structure and Its Medium-Temperature-Cured Epoxy Vitrimer System with Excellent Mechanical and Multifunctional Properties

“…The phenomenon can be mainly attributed to the combined effects of the increased α epoxy group and the reduced gel time of resin systems. A higher α epoxy group can lead to the increased cross-linked density of the DGZ system that decreases the strain, whereas a very short gel time may cause flaws such as voids within the matrix and inhomogeneous cross-linked structure (Figure S6c), which can decrease the mechanical property. − …”

Multiscale Fusion Simulation of the Influence of Temperature on the Partial Discharge Signal of GIS Insulation Void Defects

“…The model is formed by coupling the continuity equations of positive ions, electrons, and negative ions with the Poisson equation [12], [13]. The continuity equations of the three particles are shown in equations (1) In the formula, the quantities with subscripts e, p, and n represent the relative quantities of electrons, positive ions and negative ions; n represents the number density; μ represents the mobility in m 2 /(Vs); E is the vector representation of the electric field strength; μE represents the migration speed of particles; D represents the diffusion coefficient; α is the collision ionization coefficient in units of m -1 ; η is the attachment coefficient in units of m -1 ; βnp is the binding coefficient of positive and negative ions in m 3 /s; βep is the recombination coefficient of electrons and negative ions. t represents time, and Sph represents the photoionization term.…”

“…As time accumulates, the discharge will continue to degrade the insulating material, which eventually leads to a breakdown in the insulating medium, resulting in severe consequences. [1]- [3] Detection of PDs is currently recognized as an effective method to detect internal insulation defects in GIS equipment [4], but there are still many issues worth studying regarding accurately determining the severity of GIS internal defects based on the signals detected.…”

Experimental research on the influence of temperature on the discharge signal of void defects in GIS

“…High electric field strength is induced inside the void due to the small dielectric constant, causing partial discharge. The discharge continues to deteriorate the insulating material as time accumulates and causes the breakdown of the insulating medium, eventually leading to serious consequences [5][6][7].…”

“…High electric field strength is induced inside the void due to the small dielectric constant, causing partial discharge. The discharge continues to deteriorate the insulating material as time accumulates and causes the breakdown of the insulating medium, eventually leading to serious consequences [5–7]. Currently, partial discharge detection is recognised as a universal means of detecting internal insulation defects in GIS, but the extent to which the discharge signal is affected by different factors needs to be further studied.…”