Renewable energy sources (RESs), such as wind and solar generations, equip inverters to connect to the microgrids. These inverters do not have any rotating mass, thus lowering the overall system inertia. This low system inertia issue could affect the microgrid stability and resiliency in the situation of uncertainties. Today’s microgrids will become unstable if the capacity of RESs become larger and larger, leading to the weakening of microgrid stability and resilience. This paper addresses a new concept of a microgrid control incorporating a virtual inertia system based on the model predictive control (MPC) to emulate virtual inertia into the microgrid control loop, thus stabilizing microgrid frequency during high penetration of RESs. The additional controller of virtual inertia is applied to the microgrid, employing MPC with virtual inertia response. System modeling and simulations are carried out using MATLAB/Simulink^® software. The simulation results confirm the superior robustness and frequency stabilization effect of the proposed MPC-based virtual inertia control in comparison to the fuzzy logic system and conventional virtual inertia control in a system with high integration of RESs. The proposed MPC-based virtual inertia control is able to improve the robustness and frequency stabilization of the microgrid effectively.

In this study, the active and reactive power control of a battery energy storage system (BESS) using fuzzy logic control to maintain the voltage and frequency stability of the islanded Mae Sariang microgrid is presented. The main scope of the presented study is to cogitate the effectiveness of the BESS controller in view of fluctuations of frequency/voltage subjected to a disturbance occurring in the islanded microgrid. In the Mae Sariang microgrid system, the electricity is produced from two renewable energy resources (RESs), i.e., hydro and solar PV. The use of these clean energy sources has become a main problem, envisaging the output power uncertainties from RESs. Further, such power uncertainty raises power quality problems and leads to power failure. To overcome such problems, the proposed fuzzy logic control (FLC) approach is applied for the BESS controller to improve the stability of the islanded Mae Sariang microgrid. The proposed FLC is intended to provide the BESS with well-established attributes of dynamical response to disturbance, which is analyzed by a predictive model. The proposed FLC has been investigated and compared with the robust control method, which is analyzed by a mathematical model using the system identification technique. The modeling of the microgrid system with BESS is implemented and verified on the DIgSILENT PowerFactory software. The simulation result illustrates that both of the control approaches allow the dynamic stability of the microgrid and the maintenance of frequency and voltage within acceptable ranges. However, the proposed BESS fuzzy logic control is less prone to uncertainty than the BESS robust control. Furthermore, in the proposed BESS fuzzy logic control, the microgrid frequency and voltage rapidly return to their normal steady-state condition and the size of the BESS is smaller than the BESS robust control.

As electric power systems increasingly integrate Renewable Energy Sources (RESs), the consequent reduction in system inertia has heightened their sensitivity to disturbances, such as sudden load changes. This issue is especially relevant in railway power supply systems, which are evolving to be dominated by RESs. Traditional solutions, including Railway Power Conditioners (RPCs), primarily address unbalanced loads and reactive power compensation but offer limited frequency support. This paper introduces a Virtual Inertia-Integrated Railway Power Conditioner (VIIRPC), a novel solution that enhances traditional RPCs with Energy Storage Systems (ESS) to provide critical virtual inertia support, thereby addressing the critical gap in frequency stability amidst the evolving energy landscape of railway systems. Utilizing a current source-based model, the VIIRPC effectively extends inertia support from two-phase systems to balanced three-phase systems at the Point of Common Coupling (PCC). This achievement is realized by dividing a virtual inertia signal and integrating it into both sides of the RPC control loop, while respecting each side’s signal orientation. Simulations have been conducted to verify the operation under different loading conditions, including a 4-minute headway train schedule, under both conventional and low-inertia grid conditions. These results demonstrate that the VIIRPC outperforms traditional RPCs by enhancing frequency stability and maintaining conventional functionalities. This advancement is particularly significant for modern, RES-dominated railway power supplies, especially in remote areas with RES-based power sources and low short-circuit levels at the PCC.

A rapid growth in electric vehicles has led to a massive number of retired batteries in the transportation sector after 8–10 years of use. However, retired batteries retain over 60% of their original capacity and can be employed in less demanding electric vehicles or stationary energy storage systems. As a result, the management of end-of-life electric vehicles has received increased attention globally over the last decade due to their environmental and economic benefits. This work presents knowledge and technology for retired electric vehicle batteries that are applicable to the Thai context, with a particular focus on a case study of a retired lithium-ion battery from the Nissan X-Trail Hybrid car. The disassembled battery modules are designed for remanufacturing in small electric vehicles and repurposing in energy storage systems. The retired batteries were tested in a laboratory under high C-rate conditions (10C, 20C, and 30C) to examine the limitations of the batteries’ ability to deliver high current to electric vehicles during the driving operation. In addition, the electric motorcycle conversion has also been studied by converting the gasoline engine to an electric battery system. Finally, the prototypes were tested both in the laboratory and in real-world use. The findings of this study will serve as a guideline for the sorting and assessment of retired lithium-ion batteries from electric vehicles, as well as demonstrate the technical feasibility of reusing retired batteries in Thailand.

In a smart distribution grid environment, the applications of Distributed Generation (DG) are widely employed. Using these applications can have both positive and negative impacts on the distribution system. The sizing and location of their installations are the issues that should be taken into consideration to gain the maximum benefit. This paper presents an application of the Cuckoo Search (CS) for the optimal sizing and siting of DG in a smart distribution power system in order to minimize real power losses by maintaining the fault level and the voltage variation within the acceptable limit. The CS is inspired by the obligate brood parasitism of some cuckoo species by putting their eggs in the nests of other species. To demonstrate the effectiveness of the proposed methodology, a simplify 9-bus radial distribution system of the Provincial Electricity Authority of Thailand (PEA) is selected for the computer simulation with DIgSILENT software to explore the benefit of the optimal DG placement and the performance of the CS.