https://doi.org/10.5370/KIEE.2025.74.1.1

정주용(JooYong Jung) ; 김남규(NamKyu Kim) ; 권영진(YoungJin Kwon) ; 양재영(JaeYoung Yang)

In response to the increase in renewable energy sources, large-scale Energy Storage Systems (ESS) are being deployed in the power grid. When power facilities composed of large-scale plants are connected to the grid, it is necessary to verify detailed engineering assessment and grid code compliance. To successfully conduct these evaluations using power system analysis programs, detailed modeling of the ESS plant is required. This paper presents the development of a User Defined Model (UDM) for ESS plant controllers, which is essential for performing engineering assessment and assessing grid connection code of ESS plants using PSS/E, a large-scale power system analysis program. Through various case studies, it was verified that the control performance required by grid connection code could be achieved by regulating the power based on a Point Of Interconnection (POI) by the plant controller, which manages multiple inverters in the ESS plant.

https://doi.org/10.5370/KIEE.2025.74.1.7

유병찬(Byungchan Yoo) ; 최원나(Wonna Choi) ; 정승민(Seungmin Jung)

The proportion of distributed energy sources in the distribution network is rapidly increasing. Along with this, voltage management is becoming more difficult, and stability issues in the power system are being reported. Until recently, the voltage of distribution lines has generally been regulated using voltage regulators, predominantly deployed in sections where rapid voltage drops occur. However, as the characteristics of distributed energy sources are reflected, the efficiency of the voltage regulator diminishes. Therefore, cooperation with substations is necessary for stable operation of the distribution network. This paper aims to predict the operation of a machine learning-based voltage regulator to evaluate voltage fluctuations occurring in distribution lines and the corresponding control operations in advance. Long Short-Term Memory is capable of prediction on time scales. Therefore, the output characteristics of distributed energy sources can be considered. Additionally, to improve prediction accuracy, cases are generated in the OpenDSS-Python environment and additional training is performed on the LSTM model. As a result, it was confirmed that the prediction accuracy improved when the proposed method was applied. The machine learning model was verified using four evaluation indices.

https://doi.org/10.5370/KIEE.2025.74.1.15

김수현(Su-Hyeon Kim) ; 최승수(Seung-Su Choi) ; 김학군(Hak-Goon Kim) ; 임성훈(Sung-Hun Lim)

In South Korea's power distribution system, where 154 kV substations supply multiple feeders, faults on one feeder can cause voltage drops across other feeders on the same bus. These voltage drops pose significant risks to feeders with sensitive loads, such as semiconductor manufacturing facilities, which are vulnerable to voltage sags, leading to productivity and economic losses. To mitigate these issues, Under Voltage Relays (UVRs) are employed. However, coordinating UVR's operation on sound feeders with Over Current Relay (OCR) on the faulted feeder becomes more complex, especially with the application of Superconducting Fault Current Limiter (SFCL). This paper analyzes the impact of applying SFCL and induction generator (IG) on the operation of OCR and UVR in power distribution system. To address issues of UVR's maloperation and delay of OCR's operation, this study proposes adjustments to the pickup values of both relays. The results show that increasing the UVR's pickup value prevents maloperation, while lowering the OCR's pickup value reduces operation delay, improving the protection coordination between protection relays. Notably, with both SFCL and IG applied, the OCR's pickup value can be set even lower, enabling faster fault clearance. This study presents an approach for protecting sensitive loads by properly adjusting the UVR's settings on feeders vulnerable to voltage sags, thereby facilitating rapid system's recovery.

https://doi.org/10.5370/KIEE.2025.74.1.26

최승수(Seung-Su Choi) ; 김수현(Su-Hyeon Kim) ; 김학군(Hak-Goon Kim) ; 임성훈(Sung-Hun Lim)

Renewable energy has gained significant attention due to its eco-friendly nature and low carbon emissions. However, as the number of distributed energy resources (DERs) increases, they can influence the magnitude of fault currents in power systems. This change can affect the operating time of overcurrent relays (OCRs), potentially leading to large-scale blackouts or safety issues caused by overcurrent. Although research on superconducting fault current limiters (SFCLs) has been conducted to limit fault currents, the application of SFCLs in distribution systems with DERs can complicate the coordination between protective relays. In this paper, the protection coordination between OCRs in distribution system with induction generators through proper relay setting adjustment were studied.

https://doi.org/10.5370/KIEE.2025.74.1.35

전승찬(Seungchan Jeon) ; 이창희(Changhee Lee) ; 장문석(Munseok Chang) ; 황순규(Sungyu Hwang) ; 배성우(Sungwoo Bae)

This paper proposes a two-level energy management system to enhance the renewable energy integration capacity and economic operation of a power-gas sector coupled microgrid. The method was formulated as a master-slave based min-max optimization problem, considering the reactive power compensation capabilities of renewable energy resources, electrolyzer, and energy storage system. It ensured active power balance while incorporating reactive power management through its two-level structure. To validate its effectiveness, the method was compared with a benchmark system, which only considers active power balance, in an IEEE-33 bus system. The proposed method improved the average minimum voltage by 0.015 p.u. and enhanced the voltage deviation profile by 46.92%. The method reduced power purchases from the grid, saving daily operating cost by up to 211,703 KRW. These outcomes demonstrate that the proposed method enables stable and economical operation of power-gas sector coupled microgrid.

https://doi.org/10.5370/KIEE.2025.74.1.43

이경민(Kyung-Min Lee) ; 박철원(Chul-Won Park)

In order to minimize transmission constraints when delivering electric power from non-metropolitan areas to metropolitan area through the seven metropolitan tie-lines, it is necessary to construct eco-friendly power plants and transmission networks. This paper proposes the introduction of distributed pumped storage power generation utilizing the upper reservoir of an existing multipurpose hydroelectric power plant. First, based on the power system data of the 10th Basic Plan for Supply and Demand of Power, we analyze the northward current by assuming that 3GW of distributed pumped storage power generation is connected to the metropolitan area using PSS/E. We propose a congestion control method using the PTDF and GSF based on the change in the active power. Finally, we calculate the congestion of the seven metropolitan tie-lines and evaluate the effectiveness of the proposed distributed pumped storage power plant using PTDF and GSF.

https://doi.org/10.5370/KIEE.2025.74.1.49

박종훈(Jong-Hoon Park) ; 한지훈(Ji-Hoon Han) ; 최의진(Eui-Jin Choi) ; 홍선기(Sun-Ki Hong)

A hysteresis motor is a motor characterized by an increase in the efficiency of the output to input ratio during an over-excitation in which a higher voltage is applied at startup than when the rated voltage is applied, and the voltage is reduced over a period of time after entering synchronous speed. However, due to the specificity of the rotor material, finite element analysis of hysteresis motors is difficult, so the design was conducted by analyzing only the rated voltage application condition through an equivalent circuit. As a result, the improved efficiency and torque that can be achieved by over-excitation were not verified, which was confirmed by experiments after the design was completed. However, recently, finite element analysis simulation that can express the hysteresis loop behavior has become possible, so finite element analysis of hysteresis motors has become possible, and the improved efficiency and torque that can be obtained through over-excitation can be confirmed. Therefore, this paper compares the output and efficiency of hysteresis motors under over-excitation and rated voltage application, and confirms the necessity and feasibility of designing hysteresis motors considering over-excitation.

https://doi.org/10.5370/KIEE.2025.74.1.56

최대선(Daeseon Cheo) ; 김남호(Nam-Ho Kim) ; 조재훈(Jae-Hoon Cho) ; 권용준(Yong-Jun Kwon) ; 정상용(Sang-Yong Jung)

In this paper, a rotor design to reduce low order raidal force and electromagnetic vibration in interier permanent magnet synchronous motor (IPMSM) for an air compressor is proposed. First, according to the analysis results of radial force and no-load air-gap flux density of V-type 1-layer and 2-layer models, 2-layer model is selected as the initial model since it exhibits lower low radial force than 1-layer model. Additionally, the no-load air-gap flux density of the 2-layer model is further analyzed, confirming that the low order radial forces affected by order harmonic and the fundamental component of no-load air-gap flux density have a 180° phase difference, canceling each other out. Moreover, the sensitivity anlysis of rotor notches reveals that the 3-Notch model effectively increases magnitude of order harmonic. Based on the aformentionted analysis, as a result, by applying notches to the 2-layer model rotor, the low order radial force and electromagnetic vibration are reduced.

https://doi.org/10.5370/KIEE.2025.74.1.64

곽보승(Boseung Kwak) ; 김인동(In-Dong Kim)

Globally, a lot of research is being conducted on LVDC(Low Voltage Direct Current) technology due to the increase in renewable energy, microgrids, and various digital loads. Since the DC circuit breaker is essential in the LVDC systems, the importance of DC circuit breaker is also highlighted. Most LVDC systems are composed of multi-port systems. If the existing DC circuit breakers are used in this multi-port system, it is not cost-effective because the number of elements increases significantly as the number of ports increases. Therefore, a solution that can use DC circuit breakers more efficiently is needed in multi-port systems. In this paper, we propose a multi-port DC solid-state circuit breaker for LVDC multi-port systems. The proposed multi-port circuit breaker can perform blocking operations on all ports through one blocking section. In other words, even if the number of ports increases, only the main thyristor section and the auxiliary thyristor section need to be added, making it easy to expand the ports. In addition, there is an advantage that the commutation capacitor for the circuit breaker to perform a re-blocking operation can be recharged very quickly. The proposed multi-port circuit breaker is verified through experiment.

https://doi.org/10.5370/KIEE.2025.74.1.76

유준열(Jun-Yeol Ryu) ; 조수연(SuYeon Cho) ; 신양진(Yangjin Shin) ; 이동재(Dong Jae Lee) ; 설현수(Hyun-Soo Seol)

One of the most important issues in boost converter design is the minimization of size and the achievement of high power density in the coupled inductor, which is an essential component of the converter. Because the losses in the inductor inevitably increase when the size is reduced, it is necessary to change the core type. When the core type is changed, both the flux distribution and the characteristics of the inductor are also altered, so a method to accurately predict its performance is required. In consideration of these issues, an improved design for coupled inductor was developed. First, the relationship between each part of the inductor and its parameters was analyzed. Then, the appropriate core type was selected based on this investigation. In the improved design aimed at size reduction, the equivalent magnetic circuit (EMC), known for its fast computation, was constructed to reduce the computational time. The electric parameters corresponding to design variables were calculated using the EMC, and then the optimal model was selected. The accurate electric parameters and losses of the designed model were predicted through the finite element analysis. Finally, the experimental validation of the designed model was performed.

https://doi.org/10.5370/KIEE.2025.74.1.85

안병현(Byeong-Hyeon An) ; 오정식(Jeong-Sik Oh) ; 김태훈(Tae-Hun Kim) ; 박재덕(Jae-Deok Park) ; 이승윤(Seung-Yoon Lee) ; 박태식(Tae-Sik Park)

Remanufacturing is the process of disassembling, repairing, and reassembling aging products to extend their lifespan. It is an environmentally friendly approach to managing end-of-life (EOL) products, as it helps save energy and reduce carbon emissions. Many power utility companies use remanufacturing techniques, such as reconditioning transformers and circuit breakers, to prolong the service life of their equipment. However, there is limited research on developing methods or indexes to identify power equipment with high remanufacturing potential. This paper introduces a remanufacturability index for power facilities, particularly those installed during industrialization and now due for large-scale replacement. The index evaluates technical, environmental, and economic feasibility, quantifying remanufacturability by analyzing the structure and functional characteristics of the equipment.

https://doi.org/10.5370/KIEE.2025.74.1.94

황영준(Young Jun Hwang) ; 석광훈(Kwanghoon Seok) ; 김한솔(Han Sol Kim)

This paper proposes a novel Takagi-Sugeno (T-S) fuzzy model-based state feedback controller design scheme that uses an auxiliary controller to improve the performance of the adaptive cruise control (ACC) system by employing the energy-to-peak control technique. In the proposed controller design scheme, the auxiliary control input is treated as a disturbance affecting the overall control input. Then, by limiting the norm of the auxiliary control input, the energy-to-peak control technique is applied to obtain the state feedback gain which guarantees the stabilization of the ACC system represented as a T-S fuzzy model. To find the controller gain, we propose linear matrix inequality (LMI)-based sufficient conditions to ensure both asymptotic stability and the energy-to-peak performance. Finally, we show that the steady-state error of the ACC control system can be improved by using the proposed control scheme from the simulation results.

https://doi.org/10.5370/KIEE.2025.74.1.102

김종욱(Jong Wook Kim)

With the rise of real-time data collection through mobile devices such as smartphones, user-driven decision-making systems in various fields such as transportation and healthcare have advanced significantly. However, increasing concerns about the privacy of sensitive information have emerged, leading to the widespread use of differential privacy (DP) to mitigate these risks. Among DP-based data collection methods, local differential privacy (LDP) and distributed differential privacy (DDP) are prominent. While LDP provides low computational overhead, it compromises data utility, while DDP provides better utility at the cost of higher computational overhead. To address these limitations, this paper introduces a DP-compliant (,) data collection method. The proposed approach collects a fraction of of the total items and a fraction of of the total user data, achieving improved data utility compared to LDP while significantly reducing computational overhead compared to DDP, resulting in more efficient data collection. Experimental results on real-world datasets show that the proposed method not only improves data utility over LDP, but also effectively reduces computational overhead over DDP.

https://doi.org/10.5370/KIEE.2025.74.1.109

(Nebiyeleul Daniel Amare) ; 손영익(Young Ik Son)

The cascade structure control method remains widely used in industrial motor position applications due to its flexible hierarchical control loops. However, its ability to maintain nominal performance in the presence of uncertainties heavily relies on the chosen compensation strategy. Although the commonly implemented Disturbance Observer-Based Control (DOBC) approach is highly effective, it could fall short when addressing nonlinearities and unknown dynamics. To overcome these limitations, this paper considers two Radial Basis Function Neural Network (RBF-NN)-based approaches for nonlinear friction compensation under dynamic uncertainties. The robustness of the proposed scheme is validated via comparative simulations against conventional cascade controllers including a Reduced-Order PI Observer (ROPIO)-based scheme. Simulation results underscore the limitations of traditional linear controllers in handling dynamic disturbances and demonstrate the superior performance of RBF-NN-based controllers, with the supervisory RBF-NN outperforming the adaptive RBF-NN in terms of disturbance rejection.

https://doi.org/10.5370/KIEE.2025.74.1.118

이종범(Jongbeom Lee) ; 이태건(Taegun Lee) ; 주도윤(Doyoon Ju) ; 이영삼(Young Sam Lee)

This paper proposes a reinforcement learning-based control education platform utilizing Python and light-weight rapid control prototyping (LW-RCP). The platform employs the Sim-to-Real technique, in which neural networks are trained in a Python-based simulation environment and applied to real systems. The trained networks are converted into a format compatible with Matlab/Simulink. The lab-built LW-RCP is used to implement a real-time controller under the Simulink environment by incorporating the converted networks. The proposed platform allows students to easily apply reinforcement learning theory to real systems, contributing to the integration of reinforcement learning control into control curriculum. The effectiveness of the proposed platform is demonstrated by implementing a reinforcement learning controller for the pendubot system. The implemented controller performs the swing-up and transition control and exhibits strong disturbance rejection and recovery properties.

https://doi.org/10.5370/KIEE.2025.74.1.127

박무재(Mujae Park) ; 김윤아(Yun A Kim) ; 차희주(Heeju Cha) ; 이상윤(Sangyun Lee)

This study proposes a campus tour mobile application called DeepCampus that leverages deep learning-based vision technologies to enhance user engagement and interaction. The proposed application introduces two core features: a photo mission, where users take photos at designated campus locations, and a commemorative photo creation function that transforms these photos into character-based styles. The photo mission relies on a CNN-based place recognition model, trained on a custom-built campus dataset, to verify mission completion. The commemorative photo creation function uses a diffusion model to generate personalized, stylized photos, providing users with unique records of their campus experience. By integrating place recognition and generative models, the application encourages active exploration. The effectiveness of the proposed system is validated through experiments on the custom dataset, demonstrating its technical reliability and potential to enhance campus tours.

https://doi.org/10.5370/KIEE.2025.74.1.135

원형식(Hyeong-sik Won) ; 박재범(Jae-beom Park) ; 조현종(Hyun-chong Cho)

In modern society, the number of households raising pets is increasing. As pet ownership increases, the cost of treating companion cats is also rising, with a significant portion of these costs going toward the treatment of skin diseases. Skin diseases are among the common ailments in pets, and swift action is required if they occur in cats. However, early lesions lack distinctive characteristics, making accurate diagnosis difficult. Therefore, this study proposes a CADx(Computer-Aided Diagnosis) system that classifies images of cat skin conditions into inflammatory lesions, non-inflammatory lesions, and normal images using a dataset of cat skin diseases. We selected the ConvNeXt model, based on CNN, which can learn regional information and features. To learn various patterns of skin lesions, we applied Mixup, an image augmentation technique. When Mixup was applied, the model accuracy was 0.8679, showing a 3.35% improvement compared to the original dataset. Additionally, Lookahead Optimizer was applied to ensure stable learning of Mixup. When both Mixup and Lookahead Optimizer were applied, the model accuracy was 0.8741, showing a high improvement of 3.97% compared to the original dataset. Therefore, the Lookahead Optimizer helps with the stable training of mixup, which can improve the performance of the model.ㅍ

https://doi.org/10.5370/KIEE.2025.74.1.142

김민준(Min-jun Kim) ; 박재범(Jae-beom Park) ; 조현종(Hyun-chong Cho)

In contemporary society, pets are increasingly regarded as integral family members, contributing significantly to human quality of life. The growing prevalence of dog ownership has concurrently escalated the economic burden associated with veterinary care, particularly in managing common conditions like skin diseases. This study introduces an advanced deep learning-based diagnostic system for canine skin diseases, designed for practical application in home environments. We employed RandAugment to enhance data augmentation, thereby increasing the diversity of the training dataset. Furthermore, the implementation of Patterned-GridMask significantly improved the model's generalization capabilities. The use of the AdamW optimization algorithm was instrumental in mitigating overfitting, thus enhancing the model's overall learning efficiency. The proposed Transformer-based model, ViT/B-16, achieved an accuracy of 78.65% with the original dataset. With the integration of RandAugment and Patterned-GridMask techniques, the model's accuracy improved to 84.33%, underscoring its potential effectiveness for practical veterinary applications.

https://doi.org/10.5370/KIEE.2025.74.1.149

서정윤(Jeong-Yun Seo) ; 이종윤(Jong-Youn Lee) ; 박성준(Sung-Jun Park) ; 이하림(Harim Lee)

In this paper, we address the design of an AI hardware accelerator optimized for a lightweight fully-connected network. Techniques such as quantization, knowledge distillation, pruning, and low-rank approximation are utilized to reduce the number of weights, maintaining inference performance while minimizing memory requirements. We introduce a learning-based low-rank approximation that outperforms the original low rank approximation. In addition, the interrelationship between various compression techniques such as quantization, knowledge distillation, pruning, and low-rank approximation is analyzed to enhance the understanding of deep learning model compression. In order to use the decomposed weight matrices in hardware, we design a compressed fully-connected layer, utilized to construct a lightweight fully-connected network. The proposed hardware design is developed by using Verilog HDL and verified through RTL simulation.

https://doi.org/10.5370/KIEE.2025.74.1.164

엄태현(Tae-Hyun Eom) ; 백우진(Woojin Paik)

This research proposes a distance estimation method using Mono Camera-based object detection and depth estimation to generate Point Cloud data. The study aims to enhance the applicability of Mono Cameras in autonomous vehicles and robots, reducing costs compared to Stereo Camera systems. The method utilizes YOLOv8 for object detection and Depth Anything V2 for depth estimation. Results indicate that while the proposed method offers potential, it exhibits higher error rates in distance estimation compared to Stereo Camera-based approaches, primarily due to the limitations of current depth estimation technologies. The study highlights the need for further improvements in depth estimation models, particularly to address environmental factors such as lighting. Additionally, the research demonstrates that combining depth estimation with bounding box methods helps reduce estimation errors, showing promise for more stable performance. Future work will focus on improving depth estimation accuracy and making the proposed method more efficient for real-time applications, with the potential to integrate into Visual SLAM, a key technology in autonomous driving systems.

https://doi.org/10.5370/KIEE.2025.74.1.170

박성원(Sung-Won Park) ; 전희균(Heegyun Jeon) ; 황현철(Hyeon-Chyeol Hwang) ; 곽재호(Jae-Ho Kwak)

This paper deals with a localization system design for a self-driving tram vehicle that runs on a tramway track. In general, GNSS is widely used for the localization of self-driving vehicles. However, since the tram vehicle’s motion is constrained to a tramway track and GNSS signal is not always available, it is important to devise a system that can utilize other available information along the route and provide reliable localization upon the vehicle’s request. To address the issue, a localization system is developed combining GNSS/INS, tachometer, tag, and digital map. The developed system is evaluated on an actual test field and the feasibility of the developed system is validated through the test.

https://doi.org/10.5370/KIEE.2025.74.1.178

우필성(Pil-Sung Woo) ; 김유나(You-Na Kim) ; 태동현(Dong-Hyun Tae) ; 모영규(Young-Kyu Mo) ; 황민(Min Hwang) ; 김영석(Young-Seok Kim) ; 송길목(Kil-Mok Shong)

This paper proposes a diagnosis algorithm using internal resistance for a large-capacity (MWh or more) lithium-ion batteries energy storage system centered on field application. Therefore this paper identified the current status of Li-BESS construction in South Korea and analyzed the internal resistance characteristics and measurement technology. In addition the proposed diagnosis algorithm was demonstrated to reflect the specificity of the field. Future research requires more specific correlation analysis between internal resistance and BMS information.

https://doi.org/10.5370/KIEE.2025.74.1.184

윤민호(Min-Ho Yoon) ; 박찬묵(Chan-Muk Park) ; 김경탁(Kyoung-Tak Kim) ; 임성훈(Sung-Hun Lim) ; 방선배(Sun-Bae Bang)

Since the amplitude of line current generally decreases in case of a series arc occurrence in an AC line, it makes circuit breaker based on over current difficult to detect. In this paper, the AC series arc detection algorithm utilizing zero crossing period (ZCP) in time domain and fast fourier transform (FFT) in frequency domain was suggested and its effectiveness was analyzed by applying into various loads as stipulated in IEC 62606. The suggested series arc detection algorithm was designed based on the wider distribution of ZCP and the increased variation in the harmonic components with high frequency. Through its application into the measured line current obtained from series arc tests, the suggested detection algorithm was confirmed that the occurrence of series arc in loads with ZCP or with harmonic components in normal time could be distinguished and thus, the arc circuit breaker could be analyzed to detect within the regulated trip time.

https://doi.org/10.5370/KIEE.2025.74.1.190

박성준(Seong-Jun Park) ; 남준혁(Jun-Hyuk Nam) ; 류기환(Ki-Hwan Ryu) ; 김병기(Byung-Ki Kim) ; 문원식(Won-Sik Moon)

South Korea plans to achieve a 20% renewable energy share by 2030, entailing significant expansion of wind and photovoltaic system capacity. Rapid integration of distributed renewable sources into the distribution network leads to challenges intensified by high-output bifacial photovoltaic systems: overvoltage, line capacity limitations, and increased reverse power flow during peak photovoltaic system generation. Existing solutions focus on voltage constraints but have drawbacks like reduced equipment lifespan, higher costs, and do not address thermal capacity limitations. To overcome these challenges, this paper proposes an algorithm that recalculates the photovoltaic system hosting capacity by considering both voltage and thermal constraints through power flow analysis. Additionally, we suggest integrating vertical photovoltaic system installations to mitigate the reduced hosting capacity caused by bifacial modules.

https://doi.org/10.5370/KIEE.2025.74.1.198

구자영(Ja-Young Koo) ; 곽준호(Jun-Ho Kwak) ; 김희동(Hee-Dong Kim)

The stator winding of a long-term-operated high-voltage (HV) motor is subject to tracking owing to the accumulation of foreign substances, such as dust, on the surface of the end-winding. Insufficient space for phase-to-phase windings leads to damage caused by discharge. In this study, severe contamination inside the stator winding of a weather protected (WPII) of HV motor (3,700 kW, 13.2 kV) that had been in operation for approximately 15 years resulted in the detection of damage to the outer corona protection (OCP) in the slot end after cleaning work, as observed through visual inspection. After completing the conductive paint application process and global VPI(Vacuum Pressure Impregnation) re-impregnation of the stator windings, partial discharge (PD) and ultraviolet (UV) tests were conducted. After cleaning work, the PD were measured at 66,500 pC and 354,000 pC at the phase voltage (7.62 kV) and 1.25 times the phase voltage (9.53 kV), respectively. After maintenance work, the PD magnitudes significantly decreased to 20,900 pC, 26,500 pC, and 34,500 pC at the voltages of 7.62 kV, 9.53 kV, and rated voltage (13.2 kV), respectively. PD patterns were observed at 7.62 kV and 9.53 kV, with the surface discharges accompanied by 1∼2 arcs. At 13.2 kV, surface discharge with almost no arcs was observed. After cleaning work, the UV count was measured at 32,760 when the alternating current (AC) voltage was increased. The occurrence location was confirmed to be in the damaged area of the OCP. After maintenance work, UV counts were measured at the end of the end-winding corona protection (ECP) rather than at the slot end.

https://doi.org/10.5370/KIEE.2025.74.1.205

신동휘(Dong-Hwi Shin)

Electrical earthing system is being reinforced to prevent power outage by heavy lightning strike due to increased grounding resistance in 22.9kV-Y distribution network. In order to verify the value of real ground resistance reduction of electrical earthing rods after earthing reinforcement. In terms of electrical characteristics of lightning strike, transient impedance of electrical rod is considered for testing with two types of electrical rodes which contain maximized space related to soil also drilling method is implemented for minimizing soil contact resistance.

https://doi.org/10.5370/KIEE.2025.74.1.213

임훈(Hoon Lim) ; 조진석(Jin-Seok Cho) ; 조순호(Soon-Ho Cho) ; 윤병운(Byong-Un Yun) ; 방병주(Byoung-Ju Bang)

In this paper, we propose a smart multi-function notification system, a type of automation device developed to be installed on a conveyor-driven sweet potato shoot attachment machine. There are two major functions of the smart multi-function notification system. The purpose is to improve overall work productivity by improving the convenience and safety of workers and working more conveniently and safely. By conducting research and development that combines existing agricultural equipment with sensors and electronic control technologies, we hope to contribute to the long-term automation, intelligence, and unmanned use of agricultural machinery.