Effect of Conductor Impedance on Current Limiting ARC Quenching Device Performance

Low-voltage current limiting arc quenching devices are used to reduce incident energy and protect power distribution equipment from dangerous electrical arcing faults. Such devices function by applying an impedance in parallel with the arcing fault which is lower in magnitude than the impedance of the arcing fault. This forces the fault current to transfer to the lower impedance path, thus extinguishing the arcing fault. When retrofitting a current limiting arc quenching device to protect an existing piece of power distribution equipment, careful consideration must be made to minimize added conductor impedance between the quenching device and the equipment to ensure that the arc quenching device will be perform as intended. This paper describes the theoretical basis and the empirical tests used to determine the maximum allowable conductor impedance for a current limiting arc quenching device and how conductor impedance can affect arc quenching time.