• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1601-1602
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• 2007

Steam stop valves of steam turbine in the power plant are at their 100% position and have no movements. Steam control valves, ie governor valves have no movements either at their controlling position on load limit operation. By the way, if there were no change of operation state, steam valves could be sticked mechanically. Because the governor could fail in protecting and controlling steam turbine in case of emergency conditions, the closing test of 100% valve travel must be accomplished periodically for the purpose of testimony of their good conditions. And, As the difference between steam turbine structures exists according to the manufacturer or generation capacity, both steam stop valves and steam control valves differes in structure and operation method. Therefore, it is essential for not only turbine protection but also control for the control engineers to find out composition of steam valves and method of closing test.

• 전기학회논문지
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• 제66권7호
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• pp.1039-1046
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• 2017

Campus microgrid is designed and built by considering not only power generation but also power consumption management as connected microgrid type because the main goal of the campus microgrid is to save power consumption costs. There are many functions to achieve the goal and they are mainly to use generation-based functions such as islanding operation for peak management and for emergency events. In power distribution operation, Conservation Voltage Reduction (CVR) is applied in order to reduce power consumption. The CVR is defined as a function for load consumption reduction by voltage reduction in order to reduce peak demands and energy consumption. However, application of CVR to microgrid is difficult because the microgrid cannot control a tap of transformer in a substation and the microgrid normally is not designed with phase modifying equipment like a step-voltage-regulator which can control voltage in power distribution system operation. In addition, an impact of the CVR is depended on load characteristics such as a normal load, a rated power, and synchronous motors. Therefore, this paper proposes an application of CVR using linear voltage control based AVR in campus microgrid with power consumption reduction considering characteristics of load and component in the microgrid. The proposed system can be applied to each buildings by a configuration of power distribution cables; and the application results and CVR factor are presented in this paper.

• Nuclear Engineering and Technology
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• 제27권4호
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• pp.571-581
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• 1995

원자력 발전소의 비상운전절차서는 작성단계부터 난점이 많이 있고, 작성된 절차서를 착인 및 검증하는 데에도 많은 어려움이 따른다 캐나다의 원자력 규제기관인 AECB에서도 원자력발전소의 운전 허가를 받는 데 있어 발전소 비상운전 절차서를 하나의 요구조건으로 삼고 있는데, 그 요구조건은 발전소 내외의 비상상황에 대처하기 위한 상세한 계획 및 절차를 개발하는 것이다. 본 보고서에서는 미국의 원자력 발전소 비상운전 계획을 참고하고 있는 캐나다 원자력 발전소용 비상운전절차 표준지침서를 검토하고, 캐나다 비상운전 절차서 들의 현재 경향을 알아보았으며, 캔두형 발전소들의 비상운전 절차를 사고의 범위(개별적인 사고의 종류 지정), 사고진단 방법(사건 대응적, 징후 대응적, 또는 이 두 가지 방법의흔합형), 절차서 형식 등을 중점으로 비교 검토하고, 각 절차서의 내용을 포괄적으로 종합하여 현재 건설중인 월성 원자력 발전소 2, 3, 4호기용 비상운전절차서의 기본방향을 징후 대응적절차서(사고진단이 안될 경우 사용)와 논리도표와 문장이 혼합된 형식의 사건파악적절차서로 이루어진 비상운전절차서로 제시하였다.

• 산업융합연구
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• 제22권7호
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• pp.15-21
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• 2024

등산스틱은 일반적으로 산행하는 등산객 등이 보행 시 자신의 신체를 의지하면서 보행이 가능하도록 하는 보행 보조도구의 하나이다. 이러한 보조기구인 등산스틱에 다양한 기능을 수행할 수 있도록 하기 위해 충전용 배터리가 내장되어야 한다. 충전용 배터리를 충전하기 위해 별도의 전원공급장치가 필요하다. 본 연구는 자가발전 전원장치에 대한 것으로 기존의 방식보다 발전효율이 높은 스크루를 이용한 발전장치를 개발한다. 기존의 발전 방식 등과 비교 분석하고 이에 대한 문제점을 파악하여 본 연구에서 제시한 방식과 차별화를 둔다. 스크루 방식의 발전장치는 등산스틱이 지면에 접촉할 때와 지면과 떨어질 때 발전하도록 한다. 발전장치의 내장으로 별도의 전원공급장치가 필요 없고, 휴대폰 보조배터리의 역할과 조명등을 부착하여 사용할 수 있고, GPS 센서 등을 내장하여 위치 추적을 통해 길을 잃었을 때 찾을 수 있고 조명을 이용해 조난 등 위급한 상황에서 사용자의 안전을 지킬 수 있는 효과가 있다. 기존의 등산스틱 내장형 발전장치는 전류가 매우 약해 충전이 어렵고 실용성이 낫다. 본 연구에서 개발한 발전장치는 고효율을 실현하여 충분한 전류를 얻을 수 있어 배터리 충전이 가능하고 실용성이 높다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.162-164
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• 2004

Electrical power peak demand of Republic of Korea is annually growing and the peak demand has occurred in the summer. It is difficult that we handle with constructing power plants and increasing generation capacity to cope with a suddenly increased demand due to the cost problem, difficulty to find the new plant site, and the spread of the NIMBY. The alternative of the above problem is to efficiently manage demand of electrical power. Accordingly, load shedding of a section of demand side management is investigated. First we surveyed a trend of research in the domestic and overseas, for load curtailment and demand response program. After reviewing several demand response programs, the future research direction for load shedding in emergency and normal operation is introduced.

• 디지털산업정보학회논문지
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• 제12권2호
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• pp.1-6
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• 2016

Several efforts to replace the use of existing fossil energy resources have already been made around the world. As a result, a new industry of renewable energy has been created, and efficient energy distribution and storage has been promoted intensively. Among the newly explored renewable energy sources, the most widely used one is solar energy generation, which has a high market potential. An energy storage system (ESS) is a system as required. In this paper, the design and implementation of an ESS for the efficient use of power in stand-alone street lights is presented. In current ESS applied to stand-alone street lights, either 12V~24V DC (from solar power) or 110V~220V AC (from commercial power) is used to recharge power in systems with lithium batteries. In this study, an ESS that can support both solar power and commercial power was designed and implemented; it can also perform emergency recharge of portable devices from solar powered street lights. This system can maximize the scalability of ESSes using lithium batteries with efficient energy conversion, with the advantage of being an eco-friendly technology. In a ripple effect, it can also be applied to smart grids, electric vehicles, and new, renewable storage markets where energy storage technology is required.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.180-183
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• 2000

The Battery Energy Storage System(BESS) has lots of advantages such as load levelling, quick response emergency power(spinning reserve), frequency and voltage control, improvement of reliability, and deferred generation and transmission construction. The economic feasibility requires justification from the customer side of meter to promoting the dissemination of BESS nationally. In this paper, we proposed the economic assessment model of customer owned Battery Energy Storage System(BESS) which is complemented and improved the existing model. The proposed model is applied to the typical customer type(light-industrial commercial, and residential) which are taken from the statistical analysis on the load profile survey of Korea Electric Power COmpany (KEPCO). The economic assessment performed for each customer type to justifying their economic feasibility of BESS installation from the economic measures such as payback period, overall benefits, ROI, and ROR. The results of this paper are useful to the customer investment decision making and the national energy policy & strategy.

• 디지털산업정보학회논문지
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• 제12권3호
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• pp.231-257
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• 2016

Several efforts to replace the use of existing fossil energy resources have already been made around the world. As a result, a new industry of renewable energy has been created, and efficient energy distribution and storage has been promoted intensively. Among the newly explored renewable energy sources, the most widely used one is solar energy generation, which has a high market potential. An energy storage system (ESS) is a system as required. In this paper, the design and implementation of an ESS for the efficient use of power in stand-alone street lights is presented. In current ESS applied to stand-alone street lights, either 12V~24V DC (from solar power) or 110V~220V AC (from commercial power) is used to recharge power in systems with lithium batteries. In this study, an ESS that can support both solar power and commercial power was designed and implemented; it can also perform emergency recharge of portable devices from solar powered street lights. This system can maximize the scalability of ESSes using lithium batteries with efficient energy conversion, with the advantage of being an eco-friendly technology. In a ripple effect, it can also be applied to smart grids, electric vehicles, and new, renewable storage markets where energy storage technology is required.

• 한국생산제조학회지
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• 제20권6호
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• pp.805-810
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• 2011

Recently, Use of Auxiliary power unit(APU) is increasing by growing demand for improvement of insufficient electric power and installation of emergency generation devices in military tracked vehicles and civil markets. And the trend is that the units are demanded for smaller size, lighter weight and higher output power, etc to suit consumer demands. To achieve these, it is essential to develop high performance system. Therefore, in this study, it was conducted in numerical analysis to investigate flow characteristics of rotor in APU generator. Also output performance of APU applied on the rotor is analyzed by experimental method. As the result, higher rotating speed of rotor caused high air flow rate at suction and it leads to linear increase of discharging flow rate. The maximum theoretical power was achieved at 12 $m^3$/min of flow rate and, at that time, output power of generator was about 7.825 kW. Also, it can be confirmed the stabilization of output performance is achieved in about 2 seconds by experiment.

• 한국안전학회지
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• 제38권1호
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• pp.18-24
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• 2023

Severe natural disasters and man-made attacks such as terrorism are causing unprecedented disruptions in power systems. Due to rapid climate change and the aging of energy infrastructure, both the frequency of failure and the level of damage are expected to increase. Resilience is a concept proposed to respond to extreme disaster events that have a low probability of occurrence but cause enormous damage and is defined as the ability of a system to recover to its original function after a disaster. Resilience is a comprehensive indicator that can include system performance before and after a disaster and focuses on preparing for all possible disaster scenarios and having quick and efficient recovery actions after an incident. Various studies have been conducted to evaluate resilience, but studies on economic damage considering the duration of a power outage are scarce. In this study, we propose an optimal algorithm that can identify failures after an extreme disaster and restore the load on the distribution system through emergency distributed power generation input and system reconfiguration. After that, the cost of power outage damage is analyzed by applying VoLL and CDF according to each restoration strategy.