Impact of primary substation and HV faults on suburban MV network topology and total costs

The availability of electricity is of paramount importance in urban distribution networks, and one planning consideration is the way medium voltage network is protected against faults in the feeding primary substation or high voltage network. One approach is to provide primary substations with full redundancy, and another is to ensure backup from adjacent primary substations. This paper details the methodology to implement this consideration in a distribution network planning algorithm that has been under development for several years at Aalto University. A case study on a 10 kV suburban network area is demonstrated, comparing the benefit of endowing a GIS primary substation with dual HV busbars rather than just a single busbar, versus forcing backup to be available from the adjacent primary substations.