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Python 기반의 제어기 모듈화를 통한 PSS/e 과도 모의 안정성 향상 연구 A Study on Improving Stability of PSS/e Transient Simulation by Python-based Controller Modularization

https://doi.org/10.5370/KIEE.2022.71.6.803

이재형(Jaehyeong Lee) ; 신희원(Heewon Shin) ; 이상호(Sangho Lee) ; 민상원(Sang-Won Min) ; 송성윤(Sungyoon Song)

In this paper, a novel method has been proposed to solve the convergence problem driven by the target user-defined-model under the PSS/e dynamic simulation. The python-language-based control module has been developed to efficiently manage the transient simulation with a large scale of power grid database. Note that the sizes of renewable power plants have grown in such a way that their effects on the power system can no longer be neglected. In order to address these issues, it is imperative to make several power grid database so as to ensure a stable and reliable power grid. So, the objective is to maximize stable dynamic simulation run, while minimizing computing requirements to generate it. The python-based outer controller can be utilized to simulate numerous power grid database. These method can easily manage the dynamic simulation, and it provide a simple and fast simulation without requiring the user-defined-model and frequent power system control parameter change. Application of such methodology can provide higher certainty to the decision making of practical grid design.

탄소배출권 시장과 연동된 전력시장에서의 시장가격 분석모형 연구 A Study on Modeling of Market Price Analysis in Coupled Electricity and Emissions Trading Markets

https://doi.org/10.5370/KIEE.2022.71.6.812

이광호(Kwang-Ho Lee)

Emissions allowance trading has been used to assist in mitigation of greenhouse gas emissions. The scale of emissions from thermal power plants accounts for a large proportion of the total, so power generations in an electricity market play an important role in an emissions trading market. It is well known that competitive generations exercise market power in the oligopolistic electricity market. The competitive generations affect to exercise market power even in the emission trading market due to the coupled markets with the electricity market. This study proposes a coupled model for analyzing the competitive operation of power generation in terms of supply and demand for emissions allowance. According to case studies, it is shown that market power of power generations appears in the emissions trading market through the calculation of the Nash equilibrium in the proposed model.

인공지능을 활용한 디지털 트윈 기반 ESS 최적 운영 계획 모델 수립에 관한 연구 A Study on Optimal Scheduling Model of Digital Twin-based Energy Storage System using Artificial Intelligence

https://doi.org/10.5370/KIEE.2022.71.6.819

박향아(Hyang-A Park) ; 변길성(Gil-Sung Byeon) ; 김종율(Jong-Yul Kim) ; 김성신(Sung-Shin Kim)

Recently, due to the digitalization of power systems, the convergence technology of power systems and ICT has become important, and with the development of operational technologies, the importance of intelligent energy management is increasing. The importance of energy management through intelligent operating technology is emerging. In this paper, a digital twin model simulated by empirical simulation was constructed using the empirical ESS measurement data information collected from the power system. An optimal operation plan model for ESS was established by simulating the state and environment of the system in the virtual space of the digital twin similar to the actual system. It aims to improve the stable operation and efficiency of ESS through rapid situational awareness and correct decision-making by applying a data-based machine learning model rather than an existing optimization-based operation model.

변압기 보호용 비율차동계전기의 전류보상 알고리즘 분석 및 고장유형 식별로직 개발 Analysis of Current Compensation Algorithm of Ratio Differential Protective Relay for Transformer and Development of Fault Type Identification Logic

https://doi.org/10.5370/KIEE.2022.71.6.826

차지현(Ji-Hyun Cha) ; 천관호(Kwan-Ho Chun) ; 박진엽(Jin-Yeub Park)

In order to protect transformers, the ratio differential relay is widely adopted based on the differences in magnitudes and phases of currents on both sides of the transformer. Since the implementation method varies depending on ratio differential relay manufacturer, there exist some differences in the operation results of the protective relay and eventually the facility operator may have difficulties in analyzing the cause of the fault. In this paper, various electrical faults are simulated by modeling a wye-delta transformer, and the operation results of the protective relays are categorized patterned. Based on these results, a logic circuit is proposed to identify a failure in transformer fault. The fault type identification function and the operation stability of transformer is improved.

이차전지를 이용한 2kW 태양광전원용 전압보상장치의 운용 방안에 관한 연구 A Study on Operation Method of Voltage Compensation Device for 2kW PV System Using Secondary Battery

https://doi.org/10.5370/KIEE.2022.71.6.834

김병목(Byung-Mok Kim) ; 김지명(Ji-Myung Kim) ; 한병길(Byeong-Gill Han) ; 최성문(Sung-Moon Choi) ; 신건(Jian Shen) ; 노대석(Dae-Seok Rho)

Recently, korean government has been promoting numerous policies and projects to increase the capacity of renewable energy source up to 63.8[GW] by 2030, which is 20[%] of the total power generation. However, the output of PV systems may vary greatly depending on the environmental conditions, moreover, there are problems that the PV system may be disconnected from inverters as the PV string voltage violates the operation range even if partial PV modules are shaded. Therefore, in order to prevent the PV systems being disconnected from the inverter due to partial shades on PV modules, this paper presents an operation method of voltage compensation device for PV modules, which can compensate the decreased PV string voltage by connecting Li-ion batteries in series. And also, this paper performs the modeling of voltage compensation device for PV module using PSCAD/EMTDC and implements a 2kW scaled test device for voltage compensation device, accordingly. From the evaluation results of operation characteristics of voltage compensation device based on the modeling and implemented test device, it is confirmed that the proposed voltage compensation device is a useful tool for improving operation efficiency of PV systems since the input power of PV inverter can be kept within the proper operation range by compensating the decreased voltage of PV modules using series-connected Li-ion batteries when partial shades are occurred.

전기저장장치용 SPD의 최적운용 평가 알고리즘에 관한 연구 A Study on the Evaluation Algorithm for Optimal Operation of Surge Protection Device in ESS

https://doi.org/10.5370/KIEE.2022.71.6.844

황승욱(Seung-Wook Hwang) ; 김지명(Ji-Myung Kim) ; 한병길(Byeong-Gill Han) ; 최성문(Sung-Moon Choi) ; 노대석(Dae-Seok Rho)

Recently, ESS(energy storage system) for output stabilization of renewable energy source, peak demand management, frequency control, etc. is actively installed and operated. However, as the fire accidents are continuously occurred in ESS, the korean government has presented the causes of fire accidents and countermeasures for safety enhancement through the public-private joint accident investigation committee, which recommends the installation of electrical protection devices such as SPD(surge protect device) and IMD(insulation monitoring device). However, it is reported that the capacity of SPD (?  ? ) installed and operated in each ESS site is different and improper due to the absence of installation regulations. When the inappropriate capacity of SPD is adapted at DC side in ESS, there are possibilities that the battery may be negatively affected as SPD cannot properly protect the battery from the lightning and switching surges. Therefore, this paper proposes an algorithm to calculate the appropriate capacity of SPD for the stable operation of ESS and performs the modeling of surge test device, which is composed of surge generator, SPD, battery, etc., using PSCAD/EMTDC, in order to evaluate operation characteristics of SPD for the lightning and switching surges. And also this paper implements surge test device which generates 3rd class combination wave for lightning surge and switching surges. From the simulation and test results based on the presented modeling and test device, it is confirmed that the SPD can safely protect the battery from the lightning and switching surges when the proper SPD calculated by the proposed algorithm is installed.

750W 삼상유도전동기 등가회로 시험법의 슬립선정에 관한 연구 A Study on Slip Selection in the Equivalent Circuit Test Method of 750W Three-Phase Induction Motor

https://doi.org/10.5370/KIEE.2022.71.6.856

박용준(Yong-Joon Park) ; 허진(Jin Hur)

Manufacturers are using the equivalent circuit test method that can be used as a method to calculate the characteristics of the 750W three-phase motor without a motor-specific tester called the dynamometer. By selecting the slip within the limited range of the calculated output that varies depending on the slip, the test result by improved equivalent circuit method can be obtained close to the result measured by the dynamometer. And by analyzing the reproducibility of these test results and the error with the dynamometer method, and confirming their validity, it is intended to be used as a standard for the slip selection method.

삼상유도전동기 효율의 측정불확도 평가방법 연구 Study of measurement uncertainty evaluation method of three-phase induction motor efficiency

https://doi.org/10.5370/KIEE.2022.71.6.863

박용준(Yong-Joon Park) ; 허진(Jin Hur)

In this paper, we propose a method of calculating the measurement uncertainty for the result calculated through the loss separation method, which is one of the efficiency measurement methods of three-phase induction motors. The proposed algorithm calculates the uncertainty for the factors that affect the calculation of each input quantity and then proceeds according to the procedure in Table 2 using a mathematical model. To prove the validity, the efficiency of a 2.2kW three-phase induction motor was measured. The true value of efficiency considering the proposed measurement uncertainties was estimated to be in the range of 88.17 to 88.55%. By the way, considering the tolerance range (1-η)×(-15)% for the reference value 89.5% for measuring the efficiency of the three-phase induction motor, the allowable efficiency reference value is 87.93%. Therefore the estimated efficiency true value should be judged to satisfy the minimum consumption efficiency.

공정 산포에 강한 1.2 kV급 SiC MOSFET 설계 A Design of Reliable 1.2 kV SiC MOSFET against Process Deviation

https://doi.org/10.5370/KIEE.2022.71.6.871

윤효원(Hyowon Yoon) ; 김채윤(Chaeyun Kim) ; 박영은(Yeongeun Park) ; 김광재(Gwangjae Kim) ; 강규혁(Gyuhyeok Kang) ; 석오균(Ogyun Seok)

A design of a 1.2 kV SiC MOSFET for reliable characteristics against process dispersion is presented. The profile of p-base concentration was designed in consideration of incomplete ionization and electric field crowding at the gate oxide. The structure of RA-JTE was optimized in consideration of surface charge density and critical dimension. The 1.2 kV SiC MOSFET with the optimized design parameters showed reliable characteristics against process dispersion.

다중 모델 머신러닝 기반 전력사용량 예측 정확도 향상 기법 A method of multi-model machine learning for electrical energy prediction accuracy improvement

https://doi.org/10.5370/KIEE.2022.71.6.876

임정현(Jung Hyun Im) ; 성영락(Yeong Rak Seong) ; 오하령(Ha-Ryoung Oh)

The rapid increase in power consumption is increasing the importance of predicting power consumption for stable power supply. Accordingly, power consumption prediction methods using machine learning are being actively studied. RNN-based models are mainly used in systems with continuous data such as power consumption. Power consumption prediction using a single RNN-based model also shows high accuracy, but this paper proposes a multi-model-based power consumption prediction method for predicting with higher accuracy. In order to minimize noise data learning occurring in a single model, multiple models were used to learn only data that meets the learning conditions according to the conditions of the most important feature. Also, the power consumption prediction results were derived using the learned multiple models. In addition, it was verified that the prediction of power consumption using multiple models produced more accurate results compared to the prediction results of a single model.

노지 재배 스마트팜 시스템을 위한 기후 및 영상 분석 애플리케이션 Climate and Images Analyzes Application for Field Smart Farming Systems

https://doi.org/10.5370/KIEE.2022.71.6.884

김다현(Dahyeon Kim) ; 안준호(Junho Ahn) ; 윤성욱(Seongwook Youn)

This paper propose a smart farming system that can be used in a field farm. Existing smart farm research was conducted in a greenhouse or facility environment inside a building, not in a field farm. However, most crops are cultivated in an field farm. Therefore, we present a method of analyzing the existing climate and image data and deliver the analyzed results to the user through the application. In this paper, meaningful results obtained by analyzing climate data and image data are explained. Thereafter, the configuration of the application and a method of delivering information to the user will be described. In this case, the user can obtain temperature and precipitation at the place where the crop is grown through the application, and can know weeds that deviate from the line where the crop is planted. This information helps users grow crops and can maximize crop productivity.

커티너리 전차선로의 전력공급 고장 원인 상호간의 관계 분석 Analysis of the relationship between the causes of power supply failure in the catenary line

https://doi.org/10.5370/KIEE.2022.71.6.890

유기성(Ki-Seong Yu)

The catenary of the overhead single-wire country catenary is a contact wire that supplies power by mechanically and electrically contacting the pantograph (collection plate) of an electric rail vehicle whose position of power load changes. are using. In this paper, power failures occurring in the transmission and substation facilities and distribution lines of railways, centered on domestic catenary lines for the past 5 years(from 2016 to 2020), are classified by the type of failure cause, and the cause of the failure is the type of the catenary line.(7 types): Model the relationship between design errors, material defects, construction defects, negligence in maintenance, work negligence, foreign substances, and parts aging into life cycle stages(construction⇒operation⇒ disposal), and By applying the bathtub curve, which is a failure rate curve, the simulation results from a life cycle perspective derived a life cycle relationship between the causes of power failure in the overhead single-wire catenary.

생존분석 기반 배전설비 자산건전도 평가표 구성방안에 관한 연구 A Study on the Composition of Distribution Facility Health Index based on Survival Analysis

https://doi.org/10.5370/KIEE.2022.71.6.894

이혜선(Hye-Seon Lee) ; 이병성(Byung-Sung Lee) ; 오기대(Gi-Dae Oh) ; 김용하(Yong-Ha Kim)

Electric power companies conduct asset state evaluation assessments to prevent power facility failures. Asset state evaluation(called Health Index evaluation) refers to a comprehensive state evaluation of the power facility by score composed various features. Asset state evaluation is limited to power transmission facilities domestically and internationally. Therefore, in this paper, after comparing the overseas asset state evaluation methods, the survival analysis theory suitable for the domestic distribution facility data situation was used to describe the algorithm for constructing the distribution facility Health Index table.

수용가의 단상부하에 의한 전력계통 불평형 개선 연구 A Study on the Improvement of Unequilibrium in the Power System by Single Phase Load of the Receiver

https://doi.org/10.5370/KIEE.2022.71.6.901

이재환(Jae-Hwan Lee) ; 전시식(Si-Shik Jeon) ; 김영달(Young-Dal Kim)

Electricity companies supply high-quality three-phase equilibrium power to capacity. However, a single phase load of the acceptor results in an amorphous power system. In design and construction, the single-phase load is distributed equally to each phase to minimize the inequality, but inequality is inevitable due to the different time zones of use of many unspecified loads. In the acceptance area, a separate single-phase transformer is installed to supply single-phase power to minimize three-phase inequality, but installation costs and installation spaces such as single-phase transformers and special high-pressure breakers are required. To improve this irrationality, this paper aims to supply single-phase power by introducing an open△ inverse connection method to the transformer tertiary side. The second side of the three-wheel transformer supplies three-phase equilibrium power, and the third side supplies single-phase power by open△reverse connections. Compared to the single-phase power supply method by a single-phase transformer, the quantity and loss of cables on the high-pressure and low-pressure sides are the same, and special high-pressure breakers and single-phase transformers are not required. This is in accordance with the government's energy saving policy and is expected to contribute to the development of the electricity industry by reorganizing related laws and regulations so that it can be applied to the site through active review and verification.

출력 변동에 따른 유도발전기의 역률 보상기법에 관한 연구 Study on the Power Factor Compensation Technique of Induction Generator According to Output Change

https://doi.org/10.5370/KIEE.2022.71.6.909

김종겸(Jong-Gyeum Kim)

Induction generator are widely used in small-scale or micro-scale plants. Induction generators are sometimes operated at rated output, but in most cases, they are operated lower than rated output. Induction generators have an inductive load and a power factor of about 0.8 during rated operation, but the power factor drops below this when operating below the rating. A capacitor is attached to the generator terminal to compensate for the low power factor, but the capacity of this capacitor is calculated under the conditions of rated operation of the induction generator and is not suitable for output change. When the output of the generator changes, the current flowing through the stator of induction generator changes, but the excitation current required for magnetization changes very little. When the reactive power required for magnetization of the induction generator is compensated for on behalf of the power source, the power factor can be operated close to 1 even when the torque of the generator changes. In this paper, a control algorithm that can keep the power factor constant even when the output of the generator changes by installing a STATCOM(Static Synchronous Compensator) between the power supply side and the generator side is presented, and the possibility is presented through analysis.

전력량계 작업 시 아크플래시 재해 경감방안 연구 A Study on Mitigation of Injury by Arc Flash in Electronic Watt-hour Meter Work

https://doi.org/10.5370/KIEE.2022.71.6.915

김준오(Jun Oh Kim) ; 김승완(Seung Wan Kim)

About 23 million electronic Watt-hour meters are installed in Korea, and more than 2 million meters are newly installed or replaced every year. Usually, the work is performed on live line and sometimes injuries are occurred due to arc flash by improper behavior or misconnection. In Korea, Watt-hour meter workers are advised to wear personal protective equipment(PPE) level 1, but it is not reviewed well whether they can sufficiently prevent injury caused by arc flash under the guideline. In this paper, we calculate the arc flash energy according to the IEEE 1584 standard that may occur in an actual Watt-hour meter working environment and review the required PPE level by the NFPA 70E for injury prevention. In addition, an economical arc energy reduction solution is proposed instead of wearing a higher PPE level equipment. The effectiveness of the solution is verified through field experiments.