DC Current Limitation Principle Using a Helical Arc Arrangement

Abstract

The expansion of a helical arc confined between polymeric helical blades is governed by both electromagnetic and aerodynamic forces. These arise due to complex interactions between the individual arc turns, arc helical blade interactions, and surrounding media. These interactions can be exploited to control the rate of expansion. During this expansion stage, there is a substantial increase in arc voltage which, in low voltage (LV) systems, can limit the current, thereby potentially approaching current interruption provided that the arc quenching conditions are suitable. In this investigation, current limiting properties of different combinations and sizes of helical blades (metal and polymer) were studied experimentally. Marginal improvement in current-limiting properties was found upon substituting (two) outer polymeric blades with copper. Increasing the blade count was also beneficial. Blade size was, however, the most significant factor for enhancing arc control and current limitation-three large polymer blades outperforming all smaller blades-even with less blade area.

Cascaded commutation circuit for a hybrid DC breaker with dynamic control on fault current and DC breaker voltage

“…DC fault current limitation through helical arc control and mechanical circuit breaker has been proposed in [9] and [10], respectively. Both studies utilise specific design on the mechanical circuit breaker to either control the arc formation [9] or use of Thomson coil [10] to limit and interrupt the fault current. However, the mechanical circuit breaker in [9] need to factor in the large internal blades structure to enhance arc and fault current control.…”

“…Both studies utilise specific design on the mechanical circuit breaker to either control the arc formation [9] or use of Thomson coil [10] to limit and interrupt the fault current. However, the mechanical circuit breaker in [9] need to factor in the large internal blades structure to enhance arc and fault current control. Allowing arc formation can lead to subsequent structure failure and higher maintenance requirement.…”