Akademik Veri Yönetim Sistemi
10th international congress on engineering architecture and design, İstanbul, Türkiye, 24 - 26 Aralık 2022, cilt.76, sa.16, ss.1351-1362
This study seeks to verify the veracity of the concepts utilized in most of the published
articles on optimum overcurrent relays' (OCR) coordination, namely, the assumption that the
objective function (the lowest sum of operating times for the primary overcurrent relays) and its
constraint of maintaining the numerical value of the coordination time interval (CTI) ensure the
validity of OCRs' coordination in optimization algorithms. Since most distribution stations in Iraq
are similar, the Hemdan 33/11 kV substation (2 x 31.5 MVA) in Basra, south of Iraq, was chosen
as a model by considering the connection of three distribution generators (DG) to different
locations of the network. We took into account the topological change caused by the variation in
the operational state of the DGs (Turn-off and Turn-on). After conducting a comparative study
between the genetic algorithm (GA) and the biogeography-based optimization (BBO) in the
MATLAB platform, this study proves that the CTI constraint is not a guarantee of the coordination
accuracy and that the lower the value of objective function, the worse the OCRs' coordination
becomes. It also proposes an adaptive mechanism for coordinating OCRs due to changing the
operational status of the DG's connected to different sites of the network using the GA.