Vikaeristys

Vikaeristys, literally fault insulation, is a term used in electrical engineering to describe insulation that must remain functional under fault conditions or help prevent the propagation of faults through an insulation system. The concept covers the design, selection, and arrangement of insulating materials and geometries so that insulation performance is maintained during transient events, surges, or abnormal currents.

The core idea of vikaeristys is insulation coordination: ensuring that the rated dielectric strength, creepage and clearance distances, and insulation classes are appropriate for the expected fault scenarios in a system. It involves choosing materials and construction methods that can withstand briefly elevated voltages and currents without breakdown, while also providing adequate separation and barriers between live parts. Redundancy, segregation of circuits, and protective enclosures are common design approaches to enhance fault tolerance.

Testing and verification are integral to vikaeristys. Procedures may include dielectric withstand tests, partial discharge measurements, impulse (lightning) tests, and aging or thermal-stress assessments to simulate fault conditions. Modeling and simulations, such as finite element analysis, can be used to predict insulation performance under fault scenarios before physical prototypes are built.

Vikaeristys is applied across electrical equipment and installations, including power transformers, switchgear, cables, and distribution systems. It is guided by international and national standards and regulations concerning insulation coordination, insulation materials, and safety requirements. In Finnish technical literature, the concept emphasizes ensuring safety, reliability, and continued operation by maintaining insulation integrity during faults. See also insulation, dielectric strength, creepage distance, and insulation coordination.