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Development and Analysis of a Fast-Charge EV-Charging Station Model for Power Quality Assessment in Distribution Systems
(2025-09-01)
Chiradeja, Pathomthat
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Yoomak, Suntiti
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Srisuksai, Panu
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Klomjit, Jittiphong
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Ngaopitakkul, Atthapol
With the rapid rise in electric vehicle (EV) adoption, the deployment of EV charging infrastructure—particularly fast-charging stations—has expanded significantly to meet growing energy demands. While fast charging offers the advantage of reduced charging time and improved user convenience, it imposes considerable stress on existing power distribution systems due to its high power and current requirements. This study investigated the impact of EV fast charging on power quality within Thailand’s distribution network, emphasizing compliance with accepted standards such as IEEE Std 519-2014. We developed a control-oriented EV-charging station model in power systems computer-aided design and electromagnetic transients, including DC (PSCAD/EMTDC), which integrates grid-side vector control with DC fast-charging (CC/CV) behavior. Active/reactive power setpoints were mapped onto (Formula presented.) current references via Park’s transformation and regulated by proportional integral (PI) controllers with sinusoidal pulse-width modulation (SPWM) to command the voltage source converter (VSC) switches. The model enabled dynamic studies across battery state-of-charge and staggered charging schedules while monitoring voltage, current, and total harmonic distortion (THD) at both transformer sides, charger AC terminals, and DC adapters. Across all scenarios, the developed control achieved grid-current THDi of <5% and voltage THD of <1.5%, thereby meeting IEEE 519-2014 limits. These quantitative results show that the proposed, implementation-ready approach maintains acceptable power quality under diverse fast-charging patterns and provides actionable guidance for planning and scaling EV fast-charging infrastructure in Thailand’s urban networks.
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A Wildfire Risk Impact Index (WRII) for Power Distribution Systems: Integrating GIS and AHP
(2025-01-01)
Phantanaikasem, Pongpavee
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Jamroen, Chaowanan
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Surinkaew, Tossaporn
Wildfires pose a significant threat to power distribution systems, leading to disruptions, infrastructure damage, and economic losses. The conventional fire weather index (FWI) is widely used for wildfire risk assessment, but primarily relies on meteorological factors and does not explicitly account for the spatial distribution of critical infrastructure. Therefore, this study proposes a new wildfire risk impact index (WRII) to assess wildfire risk and severity on power distribution systems. The WRII is developed using the geographic information system (GIS) and analytical hierarchy process (AHP), integrating multiple spatial variables (i.e., temperature, wind speed, relative humidity, and topography), hotspot proximity to key infrastructures (i.e., power distribution systems, fire stations, and roads), and the number of connected power system points. A case study in Chiang Mai, Thailand, is conducted using the QGIS to demonstrate the applicability of WRII and its superiority over the FWI. The results highlight spatial variations in wildfire risk, offering valuable insights for power system operators. The WRII enhances wildfire preparedness and mitigation strategies.
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Characteristics of Various Single Wind-Power Distributed Generation Placements for Voltage Drop Improvement in a 22 kV Distribution System
(2024-05-01)
Ananwattanaporn, Santipont
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Thongsuk, Surakit
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Lertwanitrot, Praikanok
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Yoomak, Suntiti
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Ngamroo, Issarachai
A major challenge in distribution systems is the issue of voltage drop along the distribution line resulting from an increased load capacity connected to the utility. A significant voltage drop can affect the performance of a distribution system and cause quality issues for end users, impacting the system’s long-term sustainability and reliability. Therefore, regulations have been set stating that the voltage level should not be more that 5% higher or lower than the rated voltage. Thus, in this study, we aimed to evaluate the voltage level characteristics of a 22 kV distribution system that replicates the actual distribution system in the Provincial Electricity Authority. A voltage improvement technique based on distributed generation placement was proposed. In addition, the distribution system characteristics with and without distributed generation placement were evaluated under fault conditions. The results indicate that distributed generation placement in the distribution system can improve the voltage level along the distribution line. However, the level of increase in voltage depends on the size of the load, the capacity of the distributed generation, and the location of the distributed generation system on the distribution line. Furthermore, placing a distributed generation system with a minimum capacity at the proposed location can improve the voltage within the utility’s standard level. Thus, the installation of a distributed generation system in the distribution system is beneficial in terms of voltage improvement in the distribution system and provides the power system with a sustainable method to address the issue of voltage drop.
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Impact on Protective Device Sequence of Operation in Case Distributed Generation Integrated to Distribution System
(2023-07-01)
Ngamroo, Issarachai
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Kotesakha, Wikorn
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Yoomak, Suntiti
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Kunakorn, Anantawat
This study aims to evaluate the impact of the distributed generator (DG) connection to the grid. The simulated results present the parameters of the system required to install DG on the end of the main distribution feeder. Various parameters, such as voltage, current, and protective relay coordination are modelled after the actual provincial electricity authority (PEA) distribution system. Various case studies compared the coordination without and with DG connections to the grid by finding the difference of protective devices. The results indicate that the malfunction can be fixed in order of priority protective devices, which operate according to the parameter setting. Additionally, the coordinate functions between the recloser and fuse devices in both phase and ground configurations in the operating zone prevented the drop-out fuse melting or burning out. Based on the result, this problem is fixed by providing a directional recloser device and increasing the fuse-link rated with 40k installation for replacing the conventional sizing, which can improve the performance in case of fault occurrence to investigate the reliability and stability of the distribution system.
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Characteristic Evaluation of Wind Power Distributed Generation Sizing in Distribution System
(2023-03-01)
Ngamroo, Issarachai
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Kotesakha, Wikorn
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Yoomak, Suntiti
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Ngaopitakkul, Atthapol
Energy consumption and environmental issues have become major drivers of increasing renewable energy penetration levels. The electricity generated from renewable energy sources is decentralized throughout distributed generation (DG), which is located at the distribution level. However, the presence of DG can change distribution system characteristics and affect protection systems. Thus, this study aims to investigate the impact of DG in term of its sizing and placement on distribution systems under both normal and fault conditions. In addition, the effects on voltage improvement under normal conditions and current under fault conditions are also considered. The case study system in this study was modelled after an actual section of a 22 kV distribution line from the Provincial Electricity Authority of Thailand using PSCAD software. For DG, wind turbine generation was selected as a renewable energy source. The simulation results demonstrated that the presence of DG has a significant impact on both voltage and current characteristics under both normal and fault conditions. These impacts on the distribution system caused by DG can affect the operation of conventional distribution systems, which require further analysis and preventive measures in order to ensure good system reliability.
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Effect of Multi-wind Distributed Generators Location during Fault Occurrence in Distribution System
(2023-01-01)
Thongsuk, Surakit
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Pothisarn, Chaichan
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Jettanasen, Chaiyan
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Yoomak, Suntiti
In the recent decade, there has been a rising concern about energy consumption and environmental issues. This trend has shifted the focus of electric utility from fossil fuels to renewable energy. Thus, distributed generation (DG) that generated power from renewable energy sources has been on the rise. However, the presence of DG can affect the operation of power system protection and may cause a technical issue with the equipment. So, this paper investigates the impacts of wind power-based DG installed on the distribution system in Thailand using PSCAD software. The case study system is modeled after part of the Provincial Electricity Authority (PEA) distribution network in Northern Thailand. The comparative study with the case without DG has also been done on various parameters such as type of faults, location, and number of DG. The result from a study reveals the impact of DG on the distribution system characteristics, which changing drastically. Thus, an analysis of the impact of DG on the system must be done to address its effects and ensure the reliability of the power system.
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A Transformerless Multi-Cell Solid-State Fault Current Limiter for Medium Voltage Power System
(2018-10-22)
Techama, Pantarote
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Polmai, Sompob
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Bunlaksananusorn, Chanin
This paper proposes a transformerless solid-state fault current limiter composed of multiple cells of single-phase bridge controlled rectifier with DC reactor and an AC reactor connected in parallel with cascaded rectifier cells performing current limiting in steady state. The proposed fault current limiter can be used in medium-voltage power system without power transformer so the system is more compact. With modular design of each rectifier cell, the construction and maintenance of the system could also be simplified. In this paper, the circuit designs, the computer simulation and the construction of the solid-state fault current limiter prototype are presented. The simulation and experimental results show that the proposed fault current limiter can operate properly.
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Reliability indices estimation in PEA distribution system using ANNs
(2017-05-10)
Jiriwibhakorn, Somchat
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Kaewmanee, Keattisak
The purpose of this paper is to present the methodology of SAIFI, SAIDI and CAIDI estimation of Provincial Electricity Authority (PEA) distribution network in Thailand using Artificial Neural Networks (ANNs). The data used in this study was obtained from the Reliability Program of PEA. The feeder data from Singburi substation was used as the samples of ANNs in this research from January 2010 to October 2012. The three inputs of ANNs for reliability indices (SAIFI, SAIDI and CAIDI) consist of the number of customers behind the protective equipment, the interruption frequency of protective equipment per month and the total time interruption per month. ANNs gave the outputs (SAIFI, SAIDI and CAIDI) faster with accurate results.
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The impact of capacity and location of multidistributed generator integrated in the distribution system on electrical line losses, reliability, and interruption cost
(2015-11-01)
Chiradeja, Pathomthat
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Ngaopitakkul, Atthapol
The primary purpose of this article is to study the impact of distributed generator (DG) integrated into the distribution system in terms of electrical line losses, reliability and interruption cost. The single- and multi-distributed generators (DG) under this study are connected to a 22 kV distribution system of the Provincial Electricity Authority (PEA) that is a part of Thailand's distribution system. Geographic information systems data, including the lengths of the distribution line and the load locations that are key parameters of PEA, are simulated using digital simulation and electrical network calculation program (DIgSILENT). In addition, the capacity and location of DG installed into the distribution system are considered. The system average interruption frequency index (SAIFI), the system average interruption duration index (SAIDI) and the interruption cost are assessed as reliability indices by comparing the SAIFI, SAIDI, and interruption cost of the base case (without DG) and the cases of single- and multi-DGs connected to the distribution system. Moreover, the electrical line loss is considered in terms of active power line loss, which is also compared with the base case. The results can be summarized by focusing on the location of DG, the capacity of DG, the number of DG, the size of the load, and the distance to the load, which are factors capable of impacting the electrical line loss, SAIFI, SAIDI, and interruption cost.

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