• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1674-1688
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• 2019

As environmental pollution and fossil fuel energy problems from fuel vehicle have occurred, the interest of electric vehicle(EV) has increased. EV industry and energy industry have grown dynamically in these days. It is expected that the next generation of primary transportation will be EV, and it is necessary to prepare EV infra and efficient energy management such as EV communication protocol, EV charge station, and smart grid. Those EV and energy industry fields are now on growth. Also, the study and development of them are now in progress. In this paper, distributed charge signal processing software for smart slow and quick EV charge is proposed and designed for dealing with EV charge demand. The software consists of smart slow and quick EV charge schedule engine and EV charge power distribution core. The software is designed to support two charge station types. One is normal EV charge station and the other is bus garage EV charge station. Both two types collect the data from EV charge stations, and then analyze the collected data. The software suggests optimized EV charge schedule and deliveries EV charge power distribution information to power switchboard system, and the designed software is implemented on embedded system. It is expected that the software provides efficient EV charge schedule.

• 전기학회논문지
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• 제67권7호
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• pp.824-832
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• 2018

According to the government's policy to demonstrate and expand the renewable energy sources, distributed generators such as PV and WP are installed and operated in distribution systems. However, there are many issues related to power quality problems including over voltage and under voltage of customers. In order to overcome these problems, the electric power company have installed a step voltage regulator (SVR) in primary feeders interconnected with distributed generators, and also have established the technical guidelines for the distributed generators to stabilize the customer voltages in distribution systems. However, it is difficult to maintain the customer voltages within allowable limit. Therefore, this paper reviews the problems of voltage control by SVR in a distribution systems interconnected with a large amount of PV systems, and proposes characteristics of operating range and voltage control limit of the small hydropower generators. Also, with the estimation of the influence to the power system voltages from the voltage control mode of generators, this paper proposes the optimal voltage control algorithm of the small hydropower generators. By programming the proposed algorithm into control simulator of exciter, it is confirmed that the proposed algorithm can contribute the voltage stabilization in distribution systems interconnected with large scaled PV systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1046-1048
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• 2002

The increase of triplen harmonics in three-phase four-wire systems leads to overloaded neutral conductor, common-mode noise problems, derating of transformers, and so on. Various compensator has been designed to prevent the problems associated with the triplen harmonics. But these can not protect distribution system effectively because the triplen harmonic source is distributed extensively and distribution system type is diverse. This paper explain the operation and installation of single phase active power filter to eliminate triplen harmonics and then it is verified by simulation.

• 대한전기학회논문지:전력기술부문A
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• 제52권1호
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• pp.9-16
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• 2003

In this paper, we propose a reliability evaluation method considering the momentary interruptions of power distribution systems. The results of research are concentrated on two parts. One is the analytic and probabilistic reliability evaluation of power distribution system considering the momentary interruptions and the other is the reliability cost evaluation that unifies the cost of sustained and momentary interruptions. This proposed reliability cost evaluation methodology is also divided into the analytic and probabilistic approach and the time sequential Monte Carlo method is used for the probabilistic method. The proposed methods are tested using the modified RBTS (Roy Billinton Test System) form and historical reliability data of KEPCO (Korea Electric Power Corporation) system. Through the case studies, it is verified that the proposed reliability evaluation and its cost/worth assessment methodologies can be applied to the actual reliability studies.

• 조명전기설비학회논문지
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• 제24권10호
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• pp.49-57
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• 2010

In order to provide electricity to users economically and safely, distribution automation systems (DASs) monitor and operate components of distribution systems remotely through communication networks. The fiber optic communication network has been mainly installed for the DAS of Korea Electric Power Corporation (KEPCO) because of its huge bandwidth and dielectric noise immunity. However, the fiber optic communication network has some shortcomings that its installation cost and communication fee are expensive. This paper proposes a complex network where WLANs are combined with conventional fiber optic communication networks in order to expand DAS easily and inexpensively. A fixed wireless bridge communication unit (FWB-CU) for the proposed complex network is implemented using IEEE 802.11a WLAN technology. The proposed complex network is built actually to verify its feasibility experimentally as a DAS communication network.

• Journal of Power Electronics
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• 제19권2호
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• pp.549-559
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• 2019

This paper proposes an adaptive sliding mode control (ASMC) strategy with an enhanced optimal reaching law (EORL) for the robust current tracking control of the boost converter based hybrid power source (HPS) in an electric vehicle (EV). A conventional ASMC strategy based on state observers and the hysteresis control method is used to realize the current tracking control for the boost converter based HPS. Then a novel enhanced exponential reaching law is proposed to improve the ASMC. Moreover, an enhanced exponential reaching law is optimized by particle swarm optimization. Finally, the adaptive control factor is redesigned based on the EORL. Simulations and experiments are established to validate the ASMC strategy with the EORL. Results show that the ASMC strategy with the EORL has an excellent current tracking control effect for the boost converter based HPS. When compared with the conventional ASMC strategy, the convergence time of the ASMC strategy with the EORL can be effectively improved. In EV applications, the ASMC strategy with the EORL can achieve robust current tracking control of the boost converter based HPS. It can guarantee the active and stable power distribution for boost converter based HPS.

• 한국산학기술학회논문지
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• 제10권1호
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• pp.81-90
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• 2009

전력산업의 구조개편과 더불어 분산전원의 배전계통연계운용 및 전력품질이 전력회사의 배전사업자, 구역전기사업자, 전기공급 신뢰도와 밀접한 관계에 있는 산업용 수용가들에게 많은 관심을 불러일으키고 있다. 이러한 주변정세는 차세대의 배전계통이 다수의 Micro-grid들로 구성될 것이라고 하는 예상을 전문가들로부터 제기되기에 이르렀다. 그러나, 제안된 Micro-grid는 몇몇의 분산전원과 전력품질을 보상하는 기기, 그리고 통신제어설비와 부하들로 구성된다는 기본적인 내용에 지나지 않는다 따라서, 본 논문에서는 수용가에 고신뢰 고품질의 전력공급을 가능하게 하는 차세대 전력공급네트워크인 Micro-grid의 적정전압유지를 위한 자율분산협조 운용제어 알고리즘을 제안한다.

• 조명전기설비학회논문지
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• 제20권3호
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• pp.69-77
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• 2006

이 논문에서는 배전계통의 정전복구 알고리즘에 대해 연구하였다. 배전계통에서 정전이 발생하였을 경우, 그 피해를 최소화하기 위해 가능한 빠른 시간 내에 정전복구가 완료되어야 한다. 따라서, 본 논문에서는 광범위한 영역에 걸친 정전구간을 신속하게 복구하기 위한 2가지 방법을 연구하였다. 하나의 방안은 개별정전복구방안이며, 다른 하나는 종합정전복구방안이다. 이 방안은 복구지수를 이용하여 정전구간을 복구하는 것을 도와준다. 또한 연계점 교환법을 이용하여 과부하구간을 해소함으로써 정전복구에 일조하게 된다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.82-85
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• 2006

With the fast growing number of skyscrapers and large ultrahigh apartment complexes, the concerns on fire caused by electricity also grow. Among about 30,000 fires recorded annually, roughly one third of them are hewn to be caused by electricity. If one of such high and densely populated buildings or apartments catches a fire, the consequence can potentially be quite catastrophic. However, with the rapid development of the techniques in the fields of communications and computers, electric power distribution systems for such buildings and apartments have been largely digitalized in recent years. More detailed informations on the operating status are now available, which enables more sophisticated monitoring and early detection of potential fire caused by electricity. In this paper, we present an inference technique that can be used as one of the basic techniques in building intelligent distribution panel systems that can effectively monitor, prevent and detect the occurrence of fire caused by electricity. The technique can accommodate production rules in linguistic expressions on high abstraction levels. Fire finding strategies can be easily modified to provide more effective countermeasures. Simulation results show that inference capabilities and thus the capability of fire monitoring in power distribution panel systems can be significantly enhanced with our approach.

• 한국분무공학회지
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• 제27권1호
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• pp.11-17
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• 2022

In upcoming Post Stage-V and Tier 5 regulations of construction machineries, nitrogen oxide (NOx) emissions are strictly limited in cold start conditions. In response to this, a method of improving NOx conversion efficiency has been applied by installing an electric heating catalyst (EHC) in front of conventional urea-SCR systems so that the evaporation and thermal decomposition of urea-water solution can be promoted in cold start conditions. In this strategy, the evaporation and thermal decomposition of urea-water solution and corresponding NOx conversion efficiency are governed by temperature conditions inside the EHC. Therefore, characterizing the temperature distribution in the EHC under various operating conditions is crucial for the optimized operation and control of the EHC in Urea-SCR systems. In this study, a 1-D modeling analysis was performed to predict the heater surface temperature distribution in EHC under various operating conditions. The reliability of prediction results was verified by comparing them with measurement results obtained using an infrared (IR) camera. Based on 1-D analysis results, the effects of various EHC operation parameters on the heater surface temperature distribution were analyzed and discussed.