Mobile QR Code QR CODE : The Transactions of the Korean Institute of Electrical Engineers

시각동기 위상측정데이터를 이용한 동적 모델 제정수 추정에 관한 연구 A Study on Estimation of FACTS Dynamic Model Parameters Using PMU Data

고백경(Baekkyeong Ko) ; 남수철(Suchul Nam) ; 구본길(Bongil Koo) ; 강성범(Sungbum Kang)

FACTS is an important facility for stable power system operation by controlling the voltage of the power system. Recently, large-scale FACTS are in operation to increase the reliability of power supply, and system analysis is performed with the UWM model related to this. Although it is most accurate to perform with UWM model with high precision of analysis results, it is a good way to use a general model that can be quickly simulated for power system planning, etc. When the UWM model does not exist, general dynamic models were used for considering the dynamic characteristics of FACTS. If it is possible to estimate the parameters for the dynamic model through measurement data, the parameters in this model are considered to be more realistically applicable than before. Therefore, we developed an algorithm that estimates the parameters of FACTS using PMU data and verified the validity of the algorithm by internally verifying it through PSS/E and EMT simulations.

LSTM 기법을 이용한 풍력발전 출력 예측에 관한 연구 A Study on Wind Power Forecasting Using LSTM Method

이흥석(Heungseok Lee) ; 김규한(Kyuhan Kim) ; 정희명(Heemyung Jeong) ; 이화석(Hwaseok Lee) ; 김형수(Hyungsu Kim) ; 박준호(June Ho Park)

Recently, as the need for renewable and alternative energy increases, the proportion of wind power generation is increasing. The wind power generation can be produced anywhere in the windy place through fixed function. Commonly, the wind power generation is connected to end of system or microgrid, which have a small inertia. The wind power output depends heavily on the wind speed. So, the wind power generation generates irregular power. When irregular wind power is connected to the grid, system quality problem would occur. Therefore, in order to stabilize the system operation, it is necessary to accurately forecast the wind power and calculate the reserve power. In this paper, the LSTM(Long Short-term Memory) model was used for wind power forecasting. Also, in order to verify the accuracy of the applied method, we analyzed it by comparing with the results of ANN(Artificial Neural Network) model and SVR(Support Vector Regression) technique.

신재생에너지 수용량 증대를 위한 머신러닝을 활용한 예측 기반 배전계통 전압제어 Distribution System Voltage Control based on Forecast using Machine Learning to Increase the Hosting Capacity of Renewables

원규현(Gyu-hyun Won) ; 정일엽(Il-Yop Chung) ; 강현구(Hyun-Koo Kang)

The increase of renewable energy sources (RESs) interconnected to the distribution system can negatively affect the supply voltage regulations. This voltage problem eventually becomes an interconnection constraint for RESs. Therefore, to increase the interconnected capacity of RES stably, an appropriate voltage control which is capable of increasing the hosting capacity of the distribution system is needed. In order to solve this problem, in this paper, we proposed the voltage control method which is the OLTC (On-Load Tap Changer) tap position scheduling based on loads and RES’s generations forecast using machine learning method - feed forward neural network (FFNN), recurrent neural network (RNN), and long short term memory (LSTM) Additionally, to verify the forecasting based voltage control method proposed in this paper, the simulation result is shown the effect of increasing the hosting capacity of RESs depending on whether or not the voltage control method is applied.

국민DR 100만kW를 를 위한 스마트가전 수요반응 시범사업 실적분석 및 경제성 전망 A Study on Pilot Project Data Analysis and Economic Assessment of Smart Appliance Demand Respond Project for 1GW Peak Reduction in Korea

서인용(In-Yong Seo) ; 이창희(Chang-Hee Lee) ; 이태일(Tae-il Lee) ; 손성용(Sung-Yong Son)

With a gradual increase of electricity demand and high penetration of renewable energy resources to electrical power grid, the demand response (DR) program is emerging as an alternative to reduce peak power and increase the power system stability. This study provides an analysis of data from a DR pilot project in which 140 appliances were participated. We proposed a customer baseline load (CBL) estimation method without historic power consumption data, and calculated peak reduction effects of smart appliances. Moreover, we analyzed the average respond success rate, and investigated the effectiveness respond signal. In addition, an economic assessment of smart appliances (S/A) DR for 1GW peak reduction is performed based on the data from the pilot project. We evaluate the benefits from the application of S/A DR in the utility and participant perspective. While participant’s benefit is an incentive from the reduction of power consumption, the utility’s benefits can include deferral effects of the generation capacity and delay of transmission and distribution infra construction. Also sensitivity analysis according to various factors that affect the benefit cost ratio of the project is performed. Finally, we proposed a moderate incentive program which can attract the customer to participate the DR project.

신재생에너지 공급인증서 의 한계비용 추정에 관한 연구 A Study on the Estimation of Marginal Cost of the Renewable Energy Certificate

곽규형(Kyu-Hyeong Kwag) ; 김태현(Tae-Hyun Kim) ; 신한솔(Han-Sol Shin) ; 김수영(David Kim) ; 김욱(Wook Kim)

The Korean government currently implements Renewable Portfolio Standard(RPS) and the price of the Renewable Energy Certificate(REC) affects the profits and costs of various market players. But uncertainty over the price trend of the REC, such as the recent plunge in REC prices in the spot market and the announcement of an increase in RPS target, is increasing. However, research on the methodology of estimating the price of the REC has not been actively conducted compared to its importance. Therefore, the research on estimating marginal costs for REC is significant in that it can not only give market players the appropriate price signal but also act on various decisions based on the marginal costs derived. In this study, a mathematical model in the form of bi-level programming is established to reflect Korea’s RPS system mechanisms and to take into account changes in power market prices as large-scale renewable energy generation facilities are deployed, and then marginal costs of REC are derived using a mathematical model. It could be used for design and analysis of the REC market, such as the supply and demand situation of the market, the optimal renewable energy sources portfolio, and the impact of the RPS system mechanism

유도 전동기의 턴쇼트 고장에 관한 다이나믹 모델 연구 Study of Dynamic Model of Induction Motor with Inter-turn Short Fault

임성환(Seong-Hwan Im) ; 구본관(Bon-Gwan Gu)

An inter-turn short fault is one of the frequent induction motor faults. When the inter-turn short fault occurs, a closed-circuit loop is formed in the stator. Owing to the low impedance and coupled flux linkage voltage, a high fault current is induced in the closed loop. The high current may cause an electrical fire because of the overheated shorted wire from faults. To prevent sudden expansion of failure, a lot of diagnosis methods have been studied. In this study, dynamic models of induction motor with inter-turn short faults are developed. The proposed model is based on the deformed flux model to analyze effects from an inter-turn short fault. To verify the proposed model, a finite-element method (FEM) was applied. By using the proposed model, the inter-turn short fault can be analyzed without the complex simulation.

멀티 레벨 인버터를 갖춘 가변속 구동식 터보 공기 압축기 시스템의 동특성 해석을 위한 평균 모델 개발 Development of Average Model to Analysis Dynamic Characteristics of Variable Speed Driven Turbo Air Compressor System with Multi Level Inverter

김성안(Sung-An Kim) ; 홍경표(Kyung-Pyo Hong)

An integrated model considering the electrical and mechanical models is required to analysis a dynamic characteristics of a variable speed driven turbo air compressor system with a multi level inverter. In the electrical model, a detailed model with a small sampling time is essential because of the multi level inverter with high frequency switching operation. The small sampling time has long computation time to obtain the accurate analysis results of the system. Therefore, this paper proposes an average model of the multi level inverter to reduce the computation time. In addition, a mechanical model to analysis the dynamic characteristics of turbo air compressor system is proposed and the validity of integrated models are verified through simulation considering experimental operating conditions. The rapidity and accuracy of the proposed average model are verified by comparing with the conventional detailed model.

적응형 알고리즘을 이용한 의 제어 A MTPA Control of PMSMs Using an Adaptive algorithm

박승찬(Seung-Chan Park) ; 김상훈(Sang-hoon Kim)

In this paper, a Maximum Torque Per Ampere(MTPA) control technique using an adaptive algorithm to improve the driving efficiency of a permanent magnet synchronous motor(PMSM) is proposed. The conventional MTPA control techniques which derive current references for the MTPA control from the mathematical model is affected by the variation of motor parameters and the offset in the measured rotor position. Therefore, this paper proposes a MTPA control technique using an adaptive algorithm that only requires information of stator current magnitude. By using an adaptive algorithm, it is possible to track the optimal current angle that minimizes the copper loss for all load conditions in a short time, even in the presence of parameters error or the offset in the measured rotor position. In order to verify the effectiveness of the proposed method, simulations with 210kW and 800W Interior Permanent Magnet Synchronous Motors(IPMSMs) and experiments with an 800W IPMSM were performed.

전기추진선박의 제어전원 및 보조장치 전원공급용 인버터의 입력전압변동 시험평가 및 분석 The Test Evaluation and Analysis of Input-Voltage Variation of DC/AC Inverter in Auxiliary Power Supply of Electric Propulsion Ship

송왕근(Wang-Keun Song) ; 최용훈(Yong-Hoon Choi)

The main power supply of electric vehicles and ships is generally composed of a battery, a generator and a fuel cell, and a propulsion motor and inverter are used as a driving device. In addition to the main power supply for electric power-driven driving, additional auxiliary power supply for control system and auxiliary system is required, and power conversion devices (inverters and converters) are used for this purpose. Power conversion devices for auxiliary power supply receives power from main power supply such as battery, generator and fuel cell and performs the AC or DC power conversion. The voltage variation of main power supply depends on the usage conditions of electric propulsion system. The power conversion devices for auxiliary power supply shall not cause output stop even if the voltage of main power supply suddenly changes to the allowable voltage range. The output of the power conversion devices for auxiliary power supply shall have an operating capability to produce a stable output within the permitted voltage range. This paper deals with the test evaluation and analysis for the input voltage fluctuation of the DC/AC inverter(power conversion devices) in auxiliary power supply of electric ship..

Lombardi MOSFET - 이동도 모델을 이용한 다이아몬드 순방향 전류 전압 특성의 수치해석 시뮬레이션 Numerical Simulation for Forward Current?Voltage Characteristics of Diamond MOSFET Using Lombardi Mobility Model

김태은(Taeeun Kim) ; 이호준(Hojun Lee) ; 신승일(Seung-Il Shin) ; 하민우(Min-Woo Ha)

Diamond semiconductor technologies are suitable for power devices due to high breakdown field and high thermal conductivity. The scattering is important because it reduced the mobility and limited the on current. Here, we present numerical simulations of a p-type diamond MOSFET using Lombardi mobility model which considered the phonon, surface roughness, and Coulomb scattering-dependent hole mobility. We designed a hydrogen terminated diamond MOSFET which had the p-type diamond layer and ? two-dimensional hole gas(2DHG) channel. When the gate source and drain source voltage were -1 and -10 V, respectively, the on ? ? current with surface roughness, Coulomb, and phonon scattering were 355, 355, and 133 mA/mm, respectively. The phonon scattering by the electric field was the most dominant factor which decreased the hole mobility. The reduction in the hole mobility occurred considerably beneath the gate oxide near drain edge where the electric field concentrated.

텍스트 마이닝과 딥 러닝을 활용한 고장진단: 고장원인부서 예측 알고리즘 개발 Failure Diagnosis Using Text Mining and Deep Learning: Development of Prediction Algorithm for Responsible Department

정지영(Jiyeong Jeong) ; 김성현(Sung Hyun Kim)

Recently, as the value of text data increases, various studies on text analysis have been required, especially in the area of failure diagnosis. However, there are almost no results that systematically address the text analysis problem in the literature. Motivated by this concern, this paper focuses on developing a text analysis method that can be applied to failure diagnosis via the well-known text mining and deep learning. The main objective of this study is to analyze the failure diagnosis data of electric equipments by building an algorithm that can predict the departments (or companies) that provides the cause of the failure. To be specific, the proposed algorithm offers a possibility 1) to shorten the maintenance time, 2) to minimize labor costs, and 3) provide clear criteria of selecting subcontractor through statics and visualization. Methodologically, the data preprocessing such as feature extraction and tokenization enables the raw text data to be analyzed. After that, on the basis of machine learning and deep learning models (including CNN and RNN), various experiments are conducted to select some suitable models with high performances. Furthermore, this study makes an attempt to optimize the selected models by means of parameter tuning and dropout techniques. Finally, using the most recent data, the effectiveness of the proposed algorithm is verified.

2 LERP IT2TSK 차 추세 차분형 기반 퍼지 예측시스템 설계 및 전력부하 예측 Design of LERP-Based IT2TSK Fuzzy Prediction System with 2nd order Trend Difference and its Application to Electric Power Load Forecasting

방영근(Young-Keun Bang) ; 이철희(Chul-Heui Lee)

This paper deals with the electric power load prediction system. The first step is, in original data, making of additional information necessary to the system design by using the linear interpolation method. Next is generating the valid input data in which the rapidly increasing trend is mitigated by the 2nd order trend difference method. Final step is designing the IT2TSK fuzzy prediction system that can properly handle the uncertainty involved in the generated data. To design IT2TSK fuzzy prediction system, IT2 fuzzy sets, K-means clustering algorithm, and least square method are used individually for expressing the footprint of uncertainty, tuning the IT2 fuzzy sets, and identifying the parameters of TSK regressive model. In simulation, the performance and effectiveness of the proposed system are verified by comparing with other system after analyzing the prediction results of two types of electric power load data.

V2I Farthest point selection 가시광 통신시스템에서 기반 위치추정 기술 Farthest Point Selection-based Positioning Technology for V2I Visible Light Communications

최동녘(Dong Nyeok Choi) ; 김병욱(Byung Wook Kim)

Current trends in autonomous vehicles rely not only on GPS positioning systems, but other sensor-based systems, because general GPS cannot provide high-precision positioning capabilities. With the rapid spread of LEDs, the lighting infrastructure on the road is being replaced by LEDs and the fast switching function of the LED leads to the active research on visible light communications (VLC). This paper proposes a farthest point selection-based positioning technique which can estimate the vehicle position accurately from the captured image containing visible light data. When the absolute coordinates of multiple light sources are received, the three light sources with the longest distance between LEDs are selected and applied to the collinearity conditions for vehicle positioning. The simulation results proved that the farthest point selection-based approach can provide high-precision positioning performance even if the distance from the light source is large or low resolution camera is used.

과부하 전류로 인한 케이블 소손방지를 위한 저압 배선의 설계방법 Design Method of Low-Voltage Wiring for Preventing Cable Burnout Owing to Over-current

연기용(Ki-Yong Yeon) ; 김동규(Dong-Kyu Kim) ; 이현명(Hyeon-Myeong Lee) ; 김재언(Jae-Eon Kim)

The Korea Electro-Technical Code (KEC) was enacted in March 2018 to meet international standards and develop the country's power industry, and will be implemented in January 2021. In KEC, the protection coordination between the cable and protection devices was to be in accordance with KS C IEC 60364. In this paper, I propose the design of protection coordination between cable and protection devices applying KS C IEC 60364 to draw out the problems of the design method based on the Technical Regulation in Electricity Business Act. In addition, the application method of demand factor for economical low-voltage wiring design was proposed. For the verification of the proposed design method, the design of low-voltage wiring in a certain apartment complex was modeled, and the analysis applied with the Technical Regulation in Electricity Business Act and KS C IEC 60364 was performed. Finally, it is expected that this paper is utilized as a reference for designing economical and reasonable low-voltage wiring.

전동기가 연결된 고압케이블의 초저주파 유전정접시험에 관한 연구 A Study on the VLF-TD Test for Medium Voltage Cable Connected on the Motor

김태훈(Tae-Hoon Kim) ; 박진엽(Jin-Yeub Park) ; 차지현(Ji-Hyun Cha) ; 강민구(Min-Goo Kang)

The VLF-TD test, used as an insulation diagnostic method for high voltage cables, had to be performed with the load disconnected. If the cable is connected to the Motor during the VLF TD test, the leakage current of the cable and the leakage current of the load are measured together, so that it is difficult to accurately determine the state of the cable. In this paper, we conducted a VLF-TD test with the cable connected in the load and studied the method of calculating the VLF-TD test result of the cable using an equivalent circuit.

BESS DC 를 이용한 마이크로그리드 내의 계통 전압조정 제어에 관한 연구 A Study on Grid Voltage Regulation Control in DC Microgrid Using BESS

차대석(Dae-Seak Cha) ; 오승열(Seung-Yeol Oh) ; 고병선(Byoung-Sun Ko) ; 조선재(Sun-Jae Jo) ; 최정식(Jung-Sik Choi)

In this paper, we propose a voltage regulation control algorithm in DC micro-grid using BESS. The BESS is installed at the load end of the DC micro-grid, and the bidirectional DC/DC converter measures the grid voltage in real time to autonomously charge/discharge without external communication. The sag and swell range of the grid voltage is set to (±)5% of the rated voltage, and a VR control algorithm for this case is proposed. The proposed algorithm is verified through simulation and experiment.

전기저장장치의 제어전원용 포트 서지보호장치의 설계 및 구현에 관한 연구 Design and Implementation of 2-Port Surge Protection Device for Control Power Supply System in Energy Storage System

최형석(Hyoung-Seok Choi) ; 정태훈(Tae-Hoon Jeong) ; 태동현(Dong-Hyun Tae) ; 이후동(Hu-Dong Lee) ; 노대석(Dae-Seok Rho)

Recently, installation of renewable energies and ESS(energy storage system) has been increased to solve energy depletion and crisis of climate change. Especially, the importance of ESS is emerging as its multiple functions such as frequency regulation, power quality improvement, demand management, stabilization of renewable energy, and so on. However, the frequency of lightning strike is increasing due to rapid climate change, and then lightning surge is induced through power line, control cables and communication line and finally it leads to malfunction and damage of control power devices in ESS. Therefore, this paper proposes a design method of a 2-port surge protection device to protect the control power supply of ESS from lightning surges. And also, this paper implements a surge protection device based on the proposed method. In other words, a 2-port surge protection device is designed and implemented based on the concept of LPZ(lightning protection zone) which is defined by the international standards “IEC 62305-3” and “IEC 62305-4,” in order to protect ESS from the LEMP(lightning electromagnetic pulse) through a power line. In addition, from the test results with combination and impulse wave according to “KS C IEC 61643-11,” it is confirmed that the proposed method is useful to keep residual voltage within 1.5[kV] of surge withstanding value.

EtherNet/IP (ControlLogix) 프로토콜 기반 컨트롤로직스 와 라즈베리파이 간 통신 구현 Implementation of Communication between ControlLogix(PLC) and Raspberry Pi based on EtherNet/IP Protocol

권기백(Gi-Baek Kwon)

In this paper, based on EtherNet/IP protocol and communication interfaces with network between ControlLogix(PLC) and Raspberry Pi has the following experimental test. First, illustrates exchanging I/O data, unconnected messaging between ControlLogix and notebook using EIPScan(Ethernet/IP Scanner simulation test tool)software. Secondly, illustrates exchanging I/O data, unconnected messaging between notebook using EIPScan software and Raspberry Pi with embedded microprocessor platform. Third, illustrates exchanging I/O data, unconnected messaging between ControlLogix and raspberry pi. Finally, the experimental communication tests show the suitable solution for industrial control field, based EtherNet/IP network, can be deployed using Raspberry Pi as the adapter implemented by I/O server or messaging server.