Supply interruptions and voltage dips in smart distribution systems with feeder automation and reconfiguration

This paper analyses the impact of smart grid (SG) automation and reconfiguration functionalities on supply interruptions and voltage dips due to faults in medium voltage (MV) distribution systems. The analysis is illustrated using feeder automation and reconfiguration techniques adopted in Italy for fault detection and isolation, with reference to a simple MV homogeneous and symmetrical test network. The effects of temporary and permanent faults of different types and at different fault locations are evaluated in terms of changes of supply voltage, i.e. duration of long interruptions (LIs) and short interruption (SIs) and magnitude and duration of voltage dips (VDs), for different switching time sequences of the specific automation and reconfiguration techniques adopted. Afterwards, models of grid, automation systems, nodes and whole system are developed to allow for a more detailed and accurate evaluation of LIs, SIs and VDs, Finally, numerical analyses aimed to evaluate LI, SI and VD indices for the different automation techniques are performed and comparisons in terms of some reliability indices are reported.