Impact of Load Variations on Arcing Fault Detection in LV Distribution Networks

This presentation describes an investigation of the effects of load types and load variations in LV networks on the arcing current behaviour resulting from the downed conductors in such networks. For this target, a dedicated experimental setup was structured with a 3-phase 400/230 V, 12 mm overhead conductor supplying a variety of loading types. Three phase (3 kW) static load resistors, two 7.5 kW three phase induction motors (fed with either direct or inverter feeding) and 3.5 kW single phase induction motor (serving air conditioner) represent the variety of the considered loads. The feeding conductors were arranged to create the downed conductor condition on a certain phase covering all possibilities including the downed source-side, downed loading-side with back-infeed and downed energized conductors. Different types of faulted surface were tested including normal soil, dry sand, wet sand concrete and reinforced concrete. These types of faulted surfaces represent the most common possibilities for such faults in the Egyptian rural areas. This was facilitated with a dedicated surface sample container constructed with steel plates. The container body was solidly grounded for completing the fault current path and facilitating arcing current measurement through the same measuring system. A dedicated measuring system with accurate Hall-effect CTs and VTs was employed for capturing the corresponding voltage and current signals for analysis purposes. Different operation circumstances are considered including load addition, load removal and steady-state conditions in this study. It is expected that the obtained results will assist to realize a better understanding of the properties of these faults and supervise further research steps aiming to get a suitable scheme to detect such faults with an economic and dependable product.