Self-healing electrical insulation systems

Abstract

Self-healing materials (SHMs) are capable of autonomously repairing minor damages, thereby restoring the pre-damage characteristics of the material. Such materials are of great interest for high-voltage assets, particularly those that are difficult or prohibitively expensive to access such as underground or subsea cables, transformers, and generator stators. In these systems, preventative maintenance is rarely possible so otherwise minor damage can progress, unchecked, to failure. At this stage, it become s necessary to repair or replace the affected component, which is time-consuming and expensive. Although SHMs can represent substantial savings to systems operators, their incorporation into existing equipment designs is not trivial. As well as conferring self-healing capabilities upon the asset in question, the SHMs must be capable of functioning under operational conditions and avoid corrupting critical material properties (e.g., mechanical strength, electrical breakdown strength, etc.). The self-healing mechanism itself must also be carefully considered, as many systems will only allow a single healing cycle, or be triggered by very specific environmental conditions. Here, we illustrate these challenges with a number of examples drawn from recent research activity on self-healing systems for both solid and fluid filled insulation, and demonstrate how self-healing mechanisms can be used to effect practical self-repair.