Macquarie University
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Design and analysis of UFLS scheme for a low-inertia based power grid

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posted on 2022-03-28, 22:59 authored by S. K. Sazzad Hossain
Due to the high penetrations of renewable energy sources, a significant change to power systems' dynamic behavior following a contingency event has become a major concern in modern days. A power system's inertia is getting weaker with the integrations of renewable generators. As a result, UFLS schemes may fail to protect the frequency decline below the threshold limits with conventional settings. Inadequate load shedding during frequency excursion process may lead a cascade tripping of remaining generators, leading to a possible blackout. This thesis addresses this problem and analyses the impacts of penetration of renewable energies into grid. Here, a modified load-shedding method is proposed by considering ROCOF and the total system's damping factor. Then, it models the under-frequency relay by using MILP techniques to provide complete freedom of relays while dealing with the same problem. Furthermore, this thesis also shows a comparison of performances of these three techniques (conventional, proposed and MILP). Here, a13-bus network from real power system is considered as a test system and several case studies are conducted using the PSS/E. From simulations it is found that the proposed on-line based UFLS scheme is more efficient and one of the promising solutions to avoid blackouts



Empirical thesis. Bibliography: pages 47-50

Awarding Institution

Macquarie University

Degree Type

Thesis MRes


MRes, Macquarie University, Faculty of Science and Engineering, School of Engineering

Department, Centre or School

School of Engineering

Year of Award


Principal Supervisor

Jahangir Hossain


Copyright S K Sazzad Hossain 2018. Copyright disclaimer:




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