Extended flow algorithm for online reconfiguration of large‐scale distribution system with interconnected distributed generators

Abstract

The interconnection of distributed generators (DGs) in a power system increases the difficulty of managing the system. The minimization of the voltage deviation by network reconfiguration is an important requirement for dealing with the issue. We had previously developed a reconfiguration technique, named the intelligent flow algorithm (IFA), for determining the optimum or suboptimum network configuration within a short computation time. In the present paper, we propose an extension of IFA, named the extended flow algorithm (EFA), for more effective determination of the optimal network configuration of a distribution system containing massive installations of DGs. EFA is a two‐stage method in which the configuration that produces uniform power supply, referred to as the balanced configuration, is first generated, and then used to seek the optimal configuration using an improved branch exchange approach. Accordingly, EFA is more simplified to improve its computation speed on large‐scale systems. The algorithm was tested by case studies of different test distribution systems in the MATLAB environment, and was confirmed to have high performance to cope with DG installations and large‐scale systems. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Optimal daily schedule of reconfiguration of distribution system with interconnected photovoltaic generators

“…Power and Energy Systems Lab., Graduate School of Information Science and Technology Hokkaido University, Kita 14, Nishi 9, Kita-ku Sapporo, Hokkaido 060-0814, Japan seek the optimal configuration using an improved branch exchange approach. Higher computation speed and stability of the EFA in the presence of DGs has been confirmed by case studies comparing with other reconfiguration methodologies [15,16].…”

“…Parallel supply of loads will reduce voltage deviations of system, which is the theory mainly followed by the EFA proposed in [15]. The configurations with the load supplying to branches uniformly are called "balanced configurations" hereafter.…”

“…As a consequence, the compromise optimal configuration is obtained by the LTEFA, achieving the minimum voltage deviations for the multiple sample data, which improves the fixed configurations' time adaptability in a certain period. The corresponding constraints of reconfiguration in Section 2.3 are guaranteed in the FRM [15]. (5), can be minimized if the optimal network configuration for each time interval is found, the overall cost of the numerous switching operations for frequent reconfigurations will be extremely high, and thus the network reconfiguration at all time intervals is not economical.…”

“…In spite of the huge improvement in computation accuracy and speed, the past algorithms [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], which are called shortterm reconfiguration methods hereafter, are not really practical for system management, since their solutions are obtained based only on a single time interval's load data. However, the load condition in a distribution system dynamically varies from moment to moment; especially, the growth in the installation of DGs, e.g.…”