Optimal Switch Placement in Distribution Systems for Constraints Satisfaction in Faulted Conditions

When a constraint violation occurs due to installing a new load in a distribution system, it can be resolved by reconfiguring the distribution system. This involves changing the states of manual and remote switches to satisfy the constraints by improving voltage and current profiles in normal and faulted conditions. However, simple reconfiguration may be insufficient to address severe constraints caused by the new large load installation because power supply restoration to outage sections from healthy sections by closing remote switches when a fault occurs may become infeasible in such cases. To effectively address these severe constraints, it becomes necessary to replace manual switches on tie lines with remote switches, enabling power supply restoration by controlling remote switches. For this purpose, this paper proposes a mixed-integer linear programming (MILP) model that optimally and efficiently determines which remote switches should be replaced with manual ones while satisfying the severe constraints. The model aims to suppress the constraint violations, balance the number of sections, equalize the load capacities across sections, and minimize the number of switch replacements between remote and manual switches. The effectiveness of the proposed MILP model is demonstrated through case studies using a large-scale distribution system model with numerous manual and remote switches.