• 전기전자학회논문지
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• 제22권1호
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• pp.216-222
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• 2018

장거리 무선전력전송 기술은 단순한 핸드폰 및 소형가전을 넘어서, 4차 산업혁명의 핵심기술로 자리 잡은 드론, 로봇, 전기자동차, IoT 센서 네트워크 등에 폭넓게 적용될 수 있다. 본 논문에서는 이미 기술적으로 보편화된 기존의 근거리 무선전력전송 기술을 벗어나, 급속한 기술발전으로 통하여 상용화 단계에 이른 장거리 무선전력전송 기술의 발전방향을 살펴보고자 한다. 이를 통하여, 핵심기술을 파악과 기술적인 극복과제를 도출함으로써 국내의 연구수준과 나아갈 바를 점검하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1659-1663
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• 1991

A new control design methodology is presented here which is based on a nonlinear time-series reference model. It is indicated by highly nonlinear simulations that such designs successfully stabilize troublesome aircraft maneuvers undergoing large changes in angle of attack as well as large electric power transients due to line faults. In both applications, the nonlinear controller was significantly better than the corresponding linear adaptive controller. For the electric power network, a flexible a.c. transmission system (FACTS) with series capacitor power feedback control is studied. A bilinear auto-regressive moving average (BARMA) reference model is identified from system data and the feedback control manipulated according to a desired reference state. The control is optimized according to a predictive one-step quadratic performance index (J). A similar algorithm is derived for control of rapid changes in aircraft angle of attack over a normally unstable flight regime. In the latter case, however, a generalization of a bilinear time-series model reference includes quadratic and cubic terms in angle of attack. These applications are typical of the numerous plants for which nonlinear adaptive control has the potential to provide significant performance improvements. For aircraft control, significant maneuverability gains can provide safer transportation under large windshear disturbances as well as tactical advantages. For FACTS, there is the potential for significant increase in admissible electric power transmission over available transmission lines along with energy conservation. Electric power systems are inherently nonlinear for significant transient variations from synchronism such as may result for large fault disturbances. In such cases, traditional linear controllers may not stabilize the swing (in rotor angle) without inefficient energy wasting strategies to shed loads, etc. Fortunately, the advent of power electronics (e.g., high-speed thyristors) admits the possibility of adaptive control by means of FACTS. Line admittance manipulation seems to be an effective means to achieve stabilization and high efficiency for such FACTS. This results in parametric (or multiplicative) control of a highly nonlinear plant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1149-1152
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• 1997

This paper describes a novel approach for allocating transmission costs among users of transmission services. In the suggested approach, the cost share of each participant is proportional to amount of its line flow. To develop individual user's impact, the line utilization factors of each participant are derived by power flow equations of all nodes (i.e., load-flow equations). To deal With the slack bus problem inherent in the conventional load-flow analysis more practically, a additional power supply/demand balance equation is incorporated. Although the developed allocation rule is basically similar to the existing MW-mile method in the aspect of embedded cost allocation, it does not require to get load flow solutions of each wheeling transaction when multiple transmission transactions are considered.

• 대한전기학회논문지
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• 제41권1호
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• pp.1-8
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• 1992

Hopfield neural network has been applied to the problem of economic load dispatch(ELD) of electric power. The optimum values of neuron potentials are represented in terms of large numbers. The differential synchronous transition mode is used in this simulation. Through case studies, we have shown the possibility of the application of neural network to ELD. In case of including the transmission losses, the proposed method has an advantage that the problem can be solved simply with one neural network, without calculating incremental fuel costs and incremental losses required by traditional method.

• 한국통신학회논문지
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• 제30권12A호
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• pp.1136-1146
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• 2005

본 논문에서는 전력선 통신을 위해 사용되는 고압 배전선로에서 통신신호 및 잡음신호에 의해 방사되는 방사전계강도를 계산하였다. 전력선 통신 네트워크의 2포트 등가모델 및 기본적인 전송선로 이론을 이용해 입력임피던스를 계산하였다. 그리고 계산된 입력임피던스를 이용해 전력선상 전류를 계산하고 최종적으로 방사전계강도를 계산하였다. 전력선의 특성임피던스가 매우커서 입력 단에서의 반사가 심하기 때문에 입력임피던스는 일정한 주기를 가지는 정재파 형태를 가진다. 계산된 전류 및 방사전계 또한 이러한 형태임을 알 수 있었다. 실제 측정한 결과계산 치와 측정치가 매우 유사함을 알 수 있었다.

• KEPCO Journal on Electric Power and Energy
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• 제2권2호
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• pp.245-251
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• 2016

Despite the exponential throughput improvement in mobile communications systems, their ability to satisfy requirements of state-of-the-art and future applications of advanced metering infrastructure (AMI) is still under investigation. Challenges are mainly due to the inadequacy of third generation partnership project (3GPP) networks to support large amounts of devices simultaneously, while the number of AMI end-devices and the frequency of their data transmission increase with new AMI-based applications. In this introductory survey, innovative and future AMI applications and their communication requirements are first reviewed. Then, we identify challenges of 3GPP long term evolution (LTE) in enabling future AMI applications. More importantly, the latest improvements to LTE-A standard release 12 and 13 are reviewed and analyzed with regards to their potential to improve the quality of LTE-enabled AMI. It is found that 3GPP enhancements on machine type communications (MTC) standards will significantly enhance AMI communications. Beyond MTC specifications, non-MTC-specific enhancements such as carrier aggregation and multi-connectivity for user equipment will also contribute greatly to improving reliability and availability of AMI devices. The paper's focus is towards improved backhaul support for innovative and future AMI applications, beyond traditional automatic meter reading.

• 한국전기전자재료학회논문지
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• 제34권5호
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• pp.271-282
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• 2021

The internet of things (IoT) technology is a key component for the advent of 4^th industrial revolution, which is the network of home appliances, infrastructures, and vehicles to remotely investigate these systems. For the operation of compact IoT devices, batteries are widely used as electric power, and the limited lifetime of batteries inevitably leads to periodic replacement. Magneto-mechano-electric (MME) generators may be alternatives to batteries inside the IoT devices by converting stray magnetic field into electric energy, since we are always surrounded by ambient alternating current (AC) magnetic fields induced from electric power transmission lines everywhere. This article reviews the recent domestic research progress in high-performance MME generators and their application field for IoT and electronic devices.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.461-470
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• 2014

This paper presents a probabilistic power flow (PPF) analysis method for distribution network incorporating the randomness and correlation of photovoltaic (PV) generation. Based on the multivariate kernel density estimation theory, the probabilistic model of PV generation is proposed without any assumption of theoretical parametric distribution, which can accurately capture not only the randomness but also the correlation of PV resources at adjacent locations. The PPF method is developed by combining the proposed PV model and Monte Carlo technique to evaluate the influence of the randomness and correlation of PV generation on the performance of distribution networks. The historical power output data of three neighboring PV generators in Oregon, USA, and 34-bus/69-bus radial distribution networks are used to demonstrate the correctness, effectiveness, and application of the proposed PV model and PPF method.

• Transactions on Electrical and Electronic Materials
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• 제18권5호
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• pp.303-309
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• 2017

The flexible AC transmission system (FACTS) provides a new advanced technology solution to improve the flexibility, controllability, and stability of a power system. The unified power flow controller (UPFC) is outstanding for regulating power flow in the FACTS; it can control the real power, reactive power, and node voltage of distribution networks. This paper investigates the performance of the UPFC for power flow control with a series of step changes in rapid succession in a power system steady state and the response of the UPFC to distribution network faults and islanding mode. Simulation was carried out using the MATLAB's simulink sim power systems toolbox. The results, which were carried out on a 5-bus test system and a 4-bus multi-machine electric power system, show clearly the effectiveness and viability of UPFC in rapid response and independent control of the real and reactive power flows and oscillation damping [6].

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.335-336
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• 2015

Voltage collapse is one of the main threats in power system operation and it is a result of a very low voltage profile in one or multiple areas in the power system network. Hence, the need for proper coordination among transmission and generator operators to maintain voltage stability if of paramount importance. In this paper, the different voltage and reactive power operating guidelines and criteria of various electric reliability councils, coordinating councils, transmission system operators and other electric utilities are discussed. Among these are NERC, ENTSO-E, WECC, PJM and ERCOT. A comprehensive comparison is also made to the existing Korean power system voltage reliability guidelines. Furthermore, this paper presents a set of voltage and reactive power guidelines that can help in determining voltage limits that can improve the reliability of the Korean power system operation.