Impact of tuned harmonic filters and power factor correction capacitors on long-duration arcing fault current

Arcing fault current calculations typically use models and curves to estimate the ratio of arc current to bolted fault current. These conventional modeling techniques disregard external elements connected to the bus, such as connected loads, and storage elements such as power factor correction capacitors and tuned harmonic filters. Consequently, the calculated are current is significantly different from the actual value. Two methods are described here to calculate the magnitude of the long duration arcing fault current. The first method utilizes the per unit arcing current factors developed by Kaufmann and Page. The second method utilizes a computer model for the arc in a typical electric power system with power factor capacitors or tuned harmonic filters. The results are computed for two values of source impedance for four different test conditions. The magnitude of the arcing fault current computed using the Kaufmann and Page model agrees with the value from the computer model, for no load operating conditions establishing the accuracy of the model. The results of the computer model further show the impact of power factor capacitors and tuned harmonic filters on long duration arcing fault current.