Thermal Profiles of High-voltage Capacitor Units

High voltage capacitors are useful in power factor correction, harmonic filtering, energy storage and voltage support for modern electrical power systems. Even modest failure rates can be compounded by large numbers of assets deployed in high capacity installations, and as fuses are positioned internally or omitted in pursuit of more efficient capacitor designs, it becomes increasingly challenging to identify the location of a faulted element within a module. This paper investigates detectability of an internal heat source from distributions of temperature on a capacitor unit's outer housing. A model of a high voltage capacitor module is presented and is used to simulate the propagation of thermal energy from a heat source sited at select positions within a unit to a steel enclosure. Resultant heat distributions are shown to be readily influenced by foil arrangement and heat source location within a capacitor, since foils both direct and contain heat.