Self-Diagnosis and High-Flashover-Strength Electroluminescence Coatings

In high-voltage power equipment, insulation defects are probably generated during the production, assembly, and operation processes, which degrade the insulation materials and even cause failure under electrical stresses. As a result, various detection and diagnosis methods for insulation status have been developed to discover potential defects in equipment, but extra testing devices are usually required. Insulation materials with special stimulus–response performance, as an example, luminescence under the stimulation of intensified electric field or temperature induced by insulation defects, can be developed to realize self-detection and diagnosis of these defects. In this article, a self-diagnosis composite coating was prepared by filling electroluminescence zinc sulfide (ZnS) fillers into polydimethylsiloxane (PDMS). Two kinds of typical electrode configurations, namely, rod plane and needle plane, were processed to examine the luminescence characteristics of composite coating. The influence of the composite coating on flashover characteristics was also investigated. Experimental results indicated that ZnS composite coating exhibits obvious luminescence under relatively low voltage, and its luminance increases with electric field and ZnS content, which can effectively realize the self-detection and diagnosis function. Moreover, the composite coating can effectively improve the ac/dc surface flashover voltage. The approach presented herein provides a new insight for self-diagnosis of defects in power equipment.

I. Introduction

Insulation materials are essential components in electrical facilities, such as high-voltage (HV) power equipment, electronic devices, energy storage, and advanced spacecraft applications. Insulation defects are probably generated during the production, assembly, and operation of these facilities, which degrade the insulation materials and even cause failure. As a result, various insulation status detection and diagnosis methods have been developed to discover potential defects in equipment; however, extra testing devices, which may also affect the safe operation of the equipment, are usually required. For example, ultraviolet imager was employed to detect the corona discharges for outdoor insulators [1]. Nevertheless, most of these methods rely on expensive testing devices and require domain knowledge to diagnose the insulation status. Therefore, the development of new paradigms for nondestructive, real-time, and onsite monitoring of insulation defects is appealing for industrial applications. Due to the advantages of high sensitivity, easy identification, and real-time response, luminescent materials have been utilized in light-emitting diodes, fatigue crack visualization, and fluorescence-based diagnosis of organ-related diseases. Inspired by this, emitting insulation materials, which could produce electroluminescence in intensified-electric-field regions, are expected to realize self-detection and diagnosis of insulation defects. However, to the best of our knowledge, no research on electroluminescence-based self-diagnosis insulation materials has been reported.