Optimizing Firefly Algorithm for Directional Overcurrent Relay Coordination: A case study on the Impact of Parameter Settings

This paper investigates the application of the Firefly Algorithm for solving the coordination problem in the IEEE 3-bus network. It analyzes the impact of key parameters, including the number of generations, population size, absorption coefficient (γ), and randomization parameter (α), on the algorithms performance. Through extensive experimentation, the study demonstrates the impact on solution quality, feasibility, computational requirements, and efficiency. Results indicate that increasing the number of generations improves solution quality, but benefits diminish beyond a certain point. Feasibility improves with higher generations, but a balance between solution quality and feasibility becomes apparent at very high generations. Objective function evaluations and computation time increase linearly with generations. Larger population sizes yield better solution quality and feasibility, but a balance is observed at very high population sizes. Objective function evaluations and computation time scale proportionally with population size. The randomization parameter has a modest influence on performance, with no significant changes observed. However, extreme values impact solution quality, feasibility, and computation time. The absorption coefficient significantly affects convergence and solution quality. Lower values expedite convergence but may lead to suboptimal solutions, while higher values enhance exploration at the cost of increased computational effort. This study provides a comprehensive understanding of parameter selection and optimization in the Firefly Algorithm for solving the coordination problem of the IEEE 3-bus network, offering valuable guidance for future research in enhancing performance through parameter refinement and adaptive techniques

Recent Developments and Challenges on AC Microgrids Fault Detection and Protection Systems–A Review

The protection of AC microgrids (MGs) is an issue of paramount importance to ensure their reliable and safe operation. Designing reliable protection mechanism, however, is not a trivial task, as many practical issues need to be considered. The operation mode of MGs, which can be grid-connected or islanded, employed control strategy and practical limitations of the power electronic converters that are utilized to interface renewable energy sources and the grid, are some of the practical constraints that make fault detection, classification, and coordination in MGs different from legacy grid protection. This article aims to present the state-of-the-art of the latest research and developments, including the challenges and issues in the field of AC MG protection. A broad overview of the available fault detection, fault classification, and fault location techniques for AC MG protection and coordination are presented. Moreover, the available methods are classified, and their advantages and disadvantages are discussed

Investigation into open phase faults on transmission circuits.

Masters Degree. University of KwaZulu-Natal Natal, Durban.Open phase faults are not commonly encountered on the South African power transmission systems. However, when these faults do occur it results in major power system interruptions and spurious tripping of healthy (circuits without faults) circuits to trip without giving any indication of the type or location of the fault. This results in lengthy restoration times to find the open phase fault without any fault detection devices. The intention of this study was to investigate open phase faults and assess the impact thereof. An investigation was conducted on an open phase fault on the bussection of the transmission high voltage yard at Koeberg Power Station. The investigation utilised the Koeberg network configuration, power system data, and protection settings in order to simulate the fault and validate the results with the simulation model. The simulation model was tested by simulating short circuit faults with the current feeder circuit protection scheme characteristics and settings. The results of the investigation confirmed that the current feeder protection schemes do not take open phase fault detection into account. The back-up earth-fault protection which is normally utilised to detect and trip for high resistance faults, did indeed detect and trip for open phase faults where the unbalance currents summation was above the minimum setting threshold of 300 A although the fault clearing times was extremely long. However, this was not the case for all instances. The feeder tripped due to zero sequence currents instead of negative sequence currents. In addition the impact of open phase faults was investigated on the Koeberg generator circuit to confirm that the generator would be protected against negative sequence currents and trip based on the generator protection philosophy, the coordinated and configure generator protection settings. The literature research comprised of the present feeder protection philosophies, a review of currently used feeder protection schemes, available new feeder protection schemes, technologies available or technologies that have the potential to detect an open phase fault. An evaluation of the currently used protection schemes and new protection schemes available was conducted. Considerations with respect to the protection scheme flexibility, adaptability with regards to coordination and configuration of the protection scheme in conjunction with the feeder protection philosophies, modifications and additions to the current feeder protection schemes were considered

Artificial intelligence-based protection for smart grids

Lately, adequate protection strategies need to be developed when Microgrids (MGs) are connected to smart grids to prevent undesirable tripping. Conventional relay settings need to be adapted to changes in Distributed Generator (DG) penetrations or grid reconfigurations, which is a complicated task that can be solved efficiently using Artificial Intelligence (AI)-based protection. This paper compares and validates the difference between conventional protection (overcurrent and differential) strategies and a new strategy based on Artificial Neural Networks (ANNs), which have been shown as adequate protection, especially with reconfigurable smart grids. In addition, the limitations of the conventional protections are discussed. The AI protection is employed through the communication between all Protective Devices (PDs) in the grid, and a backup strategy that employs the communication among the PDs in the same line. This paper goes a step further to validate the protection strategies based on simulations using the MATLABTM platform and experimental results using a scaled grid. The AI-based protection method gave the best solution as it can be adapted for different grids with high accuracy and faster response than conventional protection, and without the need to change the protection settings. The scaled grid was designed for the smart grid to advocate the behavior of the protection strategies experimentally for both conventional and AI-based protections.This work is supported by Li Dak Sum Innovation Fellowship Funding (E06211200006) from the University of Nottingham Ningbo China.Peer ReviewedPostprint (published version

Transmission line protection challenges infuenced by inverter-based resources: a review

High penetration of renewable energy sources (RES) leads to new challenges for protection devices. Protection schemes are typically designed according to the dynamic behavior of rotating machines as generation sources, while the RES dynamic response, mainly governed by inverters, is not considered. Consequently, some relevant algorithms of transmission line protection are experiencing challenges because of the fact that magnitude and phase angle comparison, amount of negative-sequence, and short-circuit current level are afected by the RES. Therefore, an in-depth study of this issue is necessary, one which considers the main causes and new methodological criteria solutions. This work presents an extensive literature review of the evaluation of electrical protection performance and the efects of RES connected to a power grid through inverters. Bibliographic data on many representative publications related to this topic are obtained to show the current research lines and their proposed solutions. In addition, this work identifes the main protection functions afected and describes the new protection schemes that consider RES. Finally, an analysis and discussion of the selected bibliography are presented.Campus At

Protection Considerations of Future Distribution Networks with Large Penetration of Single Phase Residential Rooftop Photovoltaic Systems

Solar Photovoltaics now constitute a significant part of electrical power generation for many utilities around the world. This penetration of PVs introduces many technical challenges. This thesis has investigated the impact of high penetration level of single phase rooftop PVs on protection of low voltage and medium voltage and distribution networks and proposed necessary recommendation to improve the performance of protection systems of these networks

MOD-0A 200 kW wind turbine generator design and analysis report

The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented