How To Solve The Key Problem Affecting The Reliability Of Epoxy Resin Insulators: Interface Electrical Breakdown
To address the root cause of high voltage standoff insulators failure due to interfacial electrical breakdown, a two-pronged approach is needed, focusing on both material structure and interface design. Microscopic defects within pure epoxy resin (such as microbubbles, uneven crosslinking, and impurities) easily become electrical trees or initiation points for partial discharge.
An effective approach is to introduce nanofillers into the epoxy matrix, creating an interfacial transition region of approximately 1–10 nm between the nanoparticles and the resin matrix. This transition region alters the molecular chain arrangement and crosslinking density at the microscopic level, acting as a "microscopic barrier" to trap migrating free electrons, reducing their kinetic energy and thus lowering the probability of breakdown at the interface due to electron avalanche.
The type and concentration of nanofillers must be carefully selected. For example, composites using micro-Al₂O₃ particles as fillers exhibit significantly better AC breakdown strength (AC-BDS) than unfilled epoxy resins, according to statistical analysis.
On the other hand, internal defects can be controlled through rigorous manufacturing and testing processes. Internal defect detection systems, similar to ultrasonic testing, can promptly identify substandard insulating components such as bubbles and microcracks.
Combining the above technical approaches, the dual approach of interface charge regulation and composite material modification can significantly suppress interface electric field distortion and space charge accumulation, thereby reducing the reliability risk caused by interface electrical breakdown in high voltage epoxy.
