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Power Quality Improvement Based on Active Harmonic Filter in 24 kV Liquefied Natural Gas Industrial Plant’s Photovoltaic System
(2026-06-01)
Pothisarn, Chaichan
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Patcharoen, Theerasak
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Lothongkam, Chaiyaporn
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Ngaopitakkul, Atthapol
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Lertwanitrot, Praikanok
This paper presents a case study demonstrating the power quality improvements in a 24 kV distribution system at a liquefied natural gas (LNG) industrial plant with variable speed drives (VSDs), the conventional capacitor bank, and a rooftop solar photovoltaic system. Solar photovoltaic (PV) inverters can supply harmonic currents to the grid, potentially affecting the system and causing maloperation of sensitive equipment in both the utility systems and neighboring industries connected to it. Therefore, the installation of shunt active power filters (APFs) in a 400 V system was proposed in this study. The installed locations were varied, and the corresponding power qualities were analyzed. The results were examined in terms of design and harmonic elimination. Simulations were conducted using the PSCAD/EMTDC software version 4.5. The power quality simulation and field measurement results after the APF installation were compared to demonstrate the effectiveness of the proposed solutions. The addition of APFs was found to improve the power quality. In addition to the mechanism analysis, the economic feasibility of the proposed approach was investigated. The costs of APF installation in various locations were analyzed. The results show that the proposed method can improve the power supply at a reasonable price. This work contributes to sustainable industrial energy systems by improving the reliability and power quality of photovoltaic-integrated electrical networks, thereby supporting higher penetration of renewable energy resources and stable low-carbon industrial operation.
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Application of Neutral Grounding Resistor in High Voltage Photovoltaic Solar Substation System
(2025-01-01)
Pothosarn, Chaichan
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Patcharoen, Theerasak
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Srisuksai, Panu
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Ngaopitakkul, Atthapol
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Kunakorn, Anantawat
Faults in a distribution system with additional renewable energy sources can lead to unnecessary operation of protection devices due to higher detected fault currents compared to conventional systems. In addition, the voltage at the point of interconnection may temporarily drop to a low level, causing inverter-based generators to disconnect from the system. This study, therefore, proposes an investigation into the use of neutral grounding resistors in a 115 kV high-voltage (HV) substation unit located within a solar power generation system. The approach aims to limit ground fault current and reduce temporary voltage sags to maintain the connection status of inverter and ensure compliance with low voltage fault ride-through (LVRT) capability. The case study is modeled after an actual grid network consisting of two feeders, with one feeder connected to a solar power plant. PowerFactory DIgSILENT software is used to simulate the system and analyze the impact of various neutral grounding resistance values. The results of this study can be applied to the selection of neutral grounding resistors for system, helping to reduce fault current, extend relay operating time within the allowable delay range, and minimize unnecessary tripping of overcurrent protection relays in the system.
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Classification of Capacitor Bank Switching Using Fuzzy Interference Systems in 230 kV Substation
(2024-01-01)
Patcharoen, Theerasak
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Pothisarn, Chaichan
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Ngaopitakkul, Atthapol
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Ananwattanaporn, Santipont
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Lertwanitrot, Praikanok
Flexible AC transmission systems are used for enhancing the stability, transmission efficiency, and reliability of AC grids. Additionally, the most cost-effective devices for compensating reactive power are Mechanically Switched Capacitors (MSCs). This study proposes a novel algorithm for detection and capacitor bank switching transient signals in MSC, to prevent the protective relay maloperation by these transients. The Discrete wavelet transform (DWT) is used for effective time-frequency analysis and detection of measured three-phase current signals. DWT extracts the detailed wavelet coefficients of current signals at levels 1 to 30. In addition, the fuzzy inference system (FIS) has been used to determine the type of switching transient. The proposed combination of FIS and DWT has been tested on 230 kV substation and the result demonstrated precision for the identification and classification of both transient signals in MSC with 88% accuracy rate.
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Combining Fuzzy Logic and Discrete Wavelet Transform for Accurate Fault and Inrush Current Classification in High Voltage Capacitor Banks
(2024-01-01)
Songsukthawan, Panapong
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Patcharoen, Theerasak
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Ananwattanaporn, Santipont
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Yoomak, Suntiti
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Pothisarn, Chaichan
The high voltage capacitor bank is a critical component in substations, essential for maintaining power quality and system stability. However, these banks are susceptible to faults and inrush currents, posing significant operational challenges. This paper presents a method for accurately classifying fault and inrush currents in high voltage capacitor banks using Fuzzy Logic and Discrete Wavelet Transform (DWT). The DWT decomposes current waveforms into frequency components, enabling the extraction of features that characterize faults and inrush currents. These features are processed by a Fuzzy Inference System (FIS), which classifies the events based on predefined rules and membership functions. The integration of DWT and FIS provides a robust framework for distinguishing between different types of faults and inrush currents with high accuracy. Simulation results demonstrate the proposed method's efficacy, showing improved performance in classification accuracy and noise robustness compared to traditional techniques. This research enhances monitoring and protection systems in power networks, ensuring more reliable operation of high voltage capacitor banks. Implementing this method allows for better fault management and minimized downtime, leading to improved overall system efficiency and stability.
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Effect of the drop out fuse connection scheme on the overvoltage and the surge arrester in a distribution system
(2023-10-01)
Lothongkam, Chaiyaporn
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Patcharoen, Theerasak
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Yoomak, Suntiti
Overvoltage is a critical problem of Thailand’ distribution system. The electrical protection device in the distribution system needs to be able to support this level of overvoltage. In the distribution system connecting the Chachoengsao2 substation and the Bang Khla substation, the overvoltage from a ferro resonance phenomenon affects the surge arrester directly. This research studies the effect of the drop-out fuse connection scheme on the voltage and surge arrester using the RMS/EMT Simulation mode in the DIgSILENT program. Normally, the surge arrester withstands a voltage of 1.9 p.u. of the phase voltage. If the overvoltage in the distribution system is higher than the voltage that the surge arrester can withstand, the surge arrester can be damaged. Therefore, it is necessary to study and analyze the drop out fuse insertion pattern that affects the overvoltage in the distribution system to understand the causes of overvoltage problems and their effects on each type of electrical protective equipment.
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Impact of Wind Power Generation Sizing on the Characteristic of Distribution System Under Fault Condition
(2022-01-01)
Yoomak, Suntiti
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Leelajindakrairerk, Monthon
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Ngaopitakkul, Atthapol
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Ananwattanaporn, Santipont
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Songsukthawan, Panapong
In the recent decade, there has been a rising concern in energy consumption and environmental issues. This trend has shifted the electric authority to focus from fossil fuel to renewable energy. The distributed generation (DG) using a renewable energy source has been raising. The presence of DG can cause using renewable energy sources to cause a technical issue on system protection and operation. This paper aims to study the impact of different DG size installations on the distribution system in terms of the system characteristics. The study is done in both normal conditions and in cases of fault occurrence. The system using in this research is a 22-kV distribution system consists of Wind Power Generation as the DG connected into the distribution line that modeled after part of the Provincial Electricity Authority (PEA) in the northern part of Thailand. The simulation was done using PSCAD software. The result from simulation reveals the impact of DG on the distribution system characteristics in terms of significant change in the measured current and voltage signal. Thus, the analysis of the impact of DG on the system must be done to ensure the reliability of the power system.
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Voltage Drop Improvement for Distribution Systems Using High Voltage Capacitor Based-on 1/2kvar Technique
(2022-01-01)
Patcharoen, Theerasak
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Kotesakha, Wikorn
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Ngaopitakkul, Atthapol
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Thongsuk, Surakit
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Seewirote, Buncha
In this paper proposed the voltage drop improvement on distribution system with high voltage (HV) capacitors simply technique using PSCAD/EMTDC software. Considering, the HV capacitor placement techniques to improve voltage drop on the distribution system such as front load and 1/2kVar techniques are compared with base case (without the capacitor installation). The sizing and position of using HV capacitors are investigated and analyzed with the Provincial Electricity Authority (PEA) voltage regulation standard. Furthermore, the switching voltage transient occurred during each step of HV capacitor switching to the distribution system is also analyzed. The results claim that the voltage drop depends on HV capacitors placement that could be improved the voltage profile on distribution system as 5% increasing. Additionally, the transient voltage of each technique is hard to summarize, as it is reliable upon the sizing of HV capacitor switching in each step.
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Retrofitted existing residential building design in energy and economic aspect according to Thailand building energy code
(2021-02-02)
Ananwattanaporn, Santipont
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Patcharoen, Theerasak
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Bunjongjit, Sulee
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Ngaopitakkul, Atthapol
Electrical energy usage in buildings is a challenging issue because many old buildings were not originally built to achieve energy efficiency. Thus, retrofitting old buildings to net-zero buildings can benefit both the owner and electric utilities. In this study, the BEC (building energy code) software was used to evaluate energy aspects of retrofitted buildings in compliance with Thailand’s building energy code to achieve a net-zero energy building. In addition, economic aspects were also studied to verify the feasibility for a project’s owner to invest in a retrofitted existing building. An existing residential building in Thailand was used as a case study. The results in terms of energy after retrofitting existing buildings into net-zero energy buildings show that the total energy consumption can be reduced by 49.36%. From an economic perspective, the investment cost for a retrofitted building can be compensated by energy saving in terms of discounted payback period (DPP) for approximately 4.36 years and has an IRR (internal rate of return) value of 19.23%. This result evidences the potential in both energy and economy for a project’s owner to invest in a retrofitted existing building in compliance with the building code, with potential for implementation with benefits on both electrical utilities and the project’s owner.
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Design and application of daylight-based lighting controller on LED luminaire
(2020-05-01)
Bunjongjit, Sulee
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Ananwattanaporn, Santipont
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Ngaopitakkul, Atthapol
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Jettanasen, Chaiyan
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Patcharoen, Theerasak
This paper proposes a control circuit for Light Emitting Diode (LED) luminaire based on the amount of daylight. This system uses both natural daylight and artificial light from a luminaire to reach the desired illuminance on a working plane. The control circuit operates by receiving an illuminance value from a light sensor and comparing it with a set value in the microcontroller before limiting the light intensity of LED by sending a control Pulse Width Modulation (PWM) signal to the LED driver. In the experimental setup, the controller and a physical model of a working space were built in order to field test the LED daylight control circuit. Electrical characteristics such as voltage, current, and power were measured with a power meter. Illumination characteristics in terms of illuminance on a working plane were determined using a lux meter. The results from actual field tests revealed that this LED control circuit was able to reduce the power consumption of the lighting system while keeping the illuminance on the working plane at the standard value. Both simulation results and the actual experiment of the control circuit proved that it could be used to improve the energy efficiency of both newly installed and retrofitted lighting systems.
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Transient Inrush and Fault Current Signal Extraction Using Discrete Wavelet Transform for Detection and Classification in Shunt Capacitor Banks
(2020-03-01)
Patcharoen, Theerasak
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Ngaopitakkul, Atthapol
An unbalanced current protection relay (60C, 51NC) cannot operate fast enough to avoid catastrophic failure against high system fault currents within capacitor units because a traditional unbalanced current protection relay is not capable of classifying the transient fault current and switching inrush current. This article proposes a new algorithm for the detection and classification of these transient current signals. Simulations are performed using PSCAD/EMTDC programs. The outputs of the current signals are used as inputs for the discrete wavelet transform (DWT) process. The wavelet-based fault and inrush current detection and classification unit receive the captured transient current signals and use DWT to detect and analyze these signals. Actual inrush current signals from an experimental setup and shunt capacitor banks of 115 kV, 22 kV, and 6.6 kV are used to verify the proposed algorithm. The results show that the proposed algorithm provides good performance and accuracy in identifying faults and inrush currents.

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