Reliability-Oriented Electricity Distribution System Switch and Tie Line Optimization

Abstract

In the past decade, enhancing the reliability of distribution networks by means of optimal switch placement has attracted much attention. In the case of failures in a distribution feeder, such disconnect switches will isolate the faulted section, and the customers downstream of the faulted point can be supplied by neighboring feeders through tie lines. Nevertheless, such reserve branches not only might experience failures themselves but also may not even exist prior to the switch placement. Accordingly, this paper presents a mathematical-programming-based model for the concurrent placement of disconnect switches and tie lines in the distribution networks to enhance the service reliability, considering both practical benefits and drawbacks of such reserve branches. In the proposed model, installation of remote-controlled and manual switches at various locations of distribution feeders together with potential tie lines are considered. Also, practical operational constraints regarding the utilization of tie lines, and the impact of failures in such reserve branches on the reliability indices are meticulously modeled in the proposed formulation. Unreliability cost is estimated based on a reward-penalty scheme and the revenue lost due to the not supplied demand during the network contingencies. As an instance of mixed-integer linear programming, the proposed optimization model can be efficiently solved to the global optimality using commercially available software. Aiming at investigating the applicability of the proposed model, it is implemented on a test network, and the results are thoroughly analyzed through various case studies.

Planning for resilience in power distribution networks: A multi‐objective decision support

“…There has been multiple research studies conducted on optimising the location of Tie switches in distribution networks. It could be observed from References [24][25][26][27] that the Tie connection has been optimised based on various objective functions mostly from the reliability perspective to maximise DG loadability and load criticality. However, none of these Tie switch optimal placement strategies were designed to capture the resilience goals and requirements.…”

An MILP Model for Optimal Placement of Sectionalizing Switches and Tie Lines in Distribution Networks With Complex Topologies

“…Also, the authors in [22] and [23] developed MILP formulations to determine the simultaneous placement of fault indicators, MSs, and RCSs. Lastly, a new MILP model, which could specify the allocation of SSs together with the type of tie switches at reserve connection points, had been proposed in [24], and it was further developed in [25] to optimize also the number and location of tie lines.…”

“…While the MILP-based methods in [15]- [25] could be guaranteed to find the global optimal solution in a finite amount of time, they have made a couple of assumptions in their attempt to simplify the models, which have rendered them unable to be implemented on realistic DNs. First and foremost, references [15]- [18], [20]- [25] only modeled sections of the main feeders, not their laterals, thereby disregarding the impact of failures in laterals on DN reliability as well as the possibility of SS installment in the laterals. Secondly, authors in [15]- [23] assumed that the placement of tie lines and the type of the tie switches were determined prior to the optimization.…”

“…While Izadi et al in [19] addressed the former simplification by considering laterals together with main feeders as alternative locations for installing switches, they did not deal with the latter. On the contrary, authors in [24] and [25] tackled the second simplification -but not the first one. Accordingly, not only both references ignored the impact of failures and the possibility of SS installation in laterals, but also they assumed the tie switches and tie lines could be installed only at the end of main feeders.…”

“…Since the concept of the MILP models developed in [15]- [25] could not be extended to tackle the simultaneous SS and tie line optimization problem, authors in [30] attempted to do so by proposing an MILP formulation, using a different concept, so as to make the global optimal solution accessible. They proposed a two-stage fault management approach, where at its first and second stages, load restoration is accomplished by RCSs solely, and MSs and RCSs jointly, in that order.…”