Optimization of islanded microgrid considering system stability and reliability according to the dispatch strategies
Creators: name: AREFIN, Sk. Shezan
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 400705
subject: Control engineering
classificationCode: 400805
subject: Electrical energy transmission, networks and systems

description: Historically, islanded power systems were operated by conventional power sources such as diesel generator, which has detrimental effects on the environment. Renewable energy resources such as wind and solar PV could be good sources of energy to alleviate that problem; however, these sources exhibit intermittent nature. Hence, battery storage (which is an expensive option) is considered to complement the intermittency of renewables. To address these three-fold problems of emission (by diesel generator), intermittency (by wind and PV), and high investment (by the battery), this research investigates the appropriate and efficient optimization techniques and dispatch strategies to identify the optimum resource allocation for planning and operation of the islanded microgrids.

Furthermore, there could be a range of operational challenges in diesel-wind-battery microgrids in maintaining power balance, and voltage and frequency profile to ensure the secure operation of a microgrid. In the next research segments, the plan and improvement of an islanded hybrid microgrid system (IHMS) by surveying the ideal measuring of every part and the frequency, power and voltage profiles investigation for the soundness issue proof. The research and optimization area are Kangaroo Island, South Australia. The ideal estimating of the Kangaroo Island microgrid framework consolidating PV, wind, diesel generator, and battery stockpiling has been advanced for four diverse force dispatch procedures: (i) load following, (ii) cycle charging, (iii) generator order and (iv) combined dispatch. Dispatch strategies are the aspect of control, economic and power management system of islanded microgrids that keeps the connection in between energy flows and the components. Due to the stochastic nature of the meteorological conditions of any particular area and the unexpected fluctuations in the load profile of that particular may create difficulties in choosing the optimal combinations of renewable components and analysing the technical, economic and environmental benefits of the designed hybrid renewable energy system (HRES) as a complete solution of uninterrupted power supply for that area. As previously mentioned, four dispatch strategies can solve those difficulties through the comparative analysis among them. A proper energy management can be suggested and concluded after applying each dispatch techniques separately and making a brief comparative analysis among them based on system stability and reliability analysis, optimal sizes techno-economic analysis for the designed IHMS for an area.
 
This research has integrated islanded microgrid design, techno-economic analysis and power system analysis in three different software platforms to ensure the economic and technical stability and reliability of the designed IHMS. Firstly, the optimization procedure of the IHMS has been conducted for reducing the levelized cost of energy (LCOE), emission of CO2 and net present cost (NPC) with four dispatch strategies in HOMER. Secondly, the power system performances have been analysed in the MATLAB/Simulink (Simpower) platform with the optimized segment sizes of each module from HOMER. Thirdly, the power flow analysis, short circuit analysis, power system analysis and reliability analysis have been performed and reported in DIgSILENT PowerFactory. The results give the rule to gauge the age blend and required assets for the ideal activity of an islanded microgrid while keeping up force framework voltage and frequency profile, and system stability and reliability. The main contributions of this thesis articulated into three different segments as follows: (1) selection of best optimization technique according to the lowest CO2 emission, NPC and COE and best convergence rate. (2) selection of best dispatch strategy according to lowest CO2 emission, NPC and COE. (3) selection of best dispatch strategy according to the power system analysis based on the optimal sizes achieved from the techno-economic analysis.