Optimal Distribution Network Automation Considering Earth Fault Events

In the past decade, distribution network operators have been broadly engrossed toward automated distribution networks. The operators acknowledge network automation as an efficient investment toward a better service reliability. This paper aims to provide a new long-term cost/benefit analysis for an optimal level of distribution network automation. In the analysis, reduction in customer outage cost is considered as the benefit of implementing automation systems with capital investment, and annual operation and maintenance costs. In the Finnish regulation model, there is a special incentive based on customer outage cost reduction. As the main contribution of this paper, the impact of earth fault events and their required time-consuming fault management process is taken into account within the calculation of the benefit of automation systems. The solution of the analysis consists of the optimal number and location of remote-controlled sectionalizing switches, which are building blocks of automation systems. The problem is formulated in a mixed-integer linear programming format that can be effectively solved by commercially available solvers. The effectiveness of the proposed algorithm is demonstrated by applying it to the Helsinki distribution network. The results show that neglecting the impact of earth fault events can lead to suboptimal solutions.