• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.655-662
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• 2018

To respond effectively to climate change following the launch of the new climate system, the government is seeking to expand the use of distributed power resources. Among them, the district heating system centered on Combined Heat and Power (CHP) is accepted as the most realistic alternative. On the other hand, the government recently announced the change of energy paradigm focusing on eco-friendly power generation from the base power generation through $8^{th}$ Basic Plan for Long-term Electricity Supply and Demand(BPE). In this study, we analyzed the quantitative effects of profit and loss on the CHP operating business by changing patterns of the heat production, caused by the change of energy paradigm. To do this, the power market long-term simulation was carried out according to the $7^{th}$ and $8^{th}$ BPE respectively, using the commercialized power market integrated analysis program. In addition, the CHP operating model is organized to calculate the power and heat production level for each CHP operation mode by utilizing the operating performance of 830MW class CHP in Seoul metropolitan area. Based on this, the operation optimization is performed for realizing the maximum operating profit and loss during the life-cycle of CHP through the commercialized integrated energy optimization program. As a result, it can be seen that the change of the energy paradigm of the government increased the level of the ordered power supply by Korean Power Exchange(KPX), decreased the cost of the heat production, and increased the operating contribution margin by 90.9 billion won for the 30 years.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.942-945
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• 2010

The development of decentralized power has appeared as part of an effort to decrease the energy loss and the cost for electric power facilities through installing small renewable energy generation systems including solar and wind power generation. Recently a new era for decentralized power environment in building is coming in order to handle the climatic and environmental change occurred all over the world. Especially solar and wind power generation systems can be easily set up and are also economically feasible, and thus many industrial companies enter into this business. This paper suggests the overall architecture for the decentralized renewable power system and the prediction method of power on climatic change. The ultimate goal is to help manage the overall power efficiently and thus provide the technological basis for achieving zero-energy house.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.707-714
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• 2010

When problems such as line fault, breakdown of a substation or a generator, etc. arise on the grid, the Microgrid is designed to be separated or isolated from the grid. Most existing DGs(Distributed Generators) in distribution system use rotating machine. However, new DGs such as micro gas turbine, fuel cell, photo voltaic, wind turbine, etc. will be interfaced with the Microgrid through an inverter. So the Microgrid may have very lower inertia than the conventional distribution system. By the way, the rate of change of frequency depends on the inertia of the power system. Moreover, frequency has a strong coupling with active power in power system. Because the frequency of the Microgrid may change rapidly and largely during transient, appropriate and fast control strategy is needed for stable operation of the Microgrid. Therefore, this paper presents a power balancing strategy in Microgrid during transient. Despite of strong power or frequency excursions, power balancing in the Microgrid can be maintained.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.4
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• pp.75-79
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• 2013

A power distribution network (PDN) is a network that provides connection between the voltage source supply and the power/ground terminals of a microprocessor chip. It consists of a voltage regulator module, a printed circuit board, a package substrate, a microprocessor chip as well as decoupling capacitors. For power integrity analysis, the board and package layouts have to be transformed into an electrical network of resistor, inductor and capacitor components which may be expressed using the S-parameters models. This modeling process generally takes from several hours up to a few days for a complete board or package layout. When the board and package layouts change, they need to be re-extracted and the S-parameters models also need to be re-generated for power integrity assessment. This not only consumes a lot of resources such as time and manpower, the task of PDN modeling is also tedious and mundane. In this paper, a block-based PDN modeling is proposed. Here, the board or package layout is partitioned into sub-blocks and each of them is modeled independently. In the event of a change in power rails routing, only the affected sub-blocks will be reextracted and re-modeled. Simulation results show that the proposed block-based PDN modeling not only can save at least 75% of processing time but it can, at the same time, keep the modeling accuracy on par with the traditional PDN modeling methodology.

• Journal of Magnetics
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• v.19 no.2
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• pp.197-204
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• 2014

A transcranial magnetic stimulation device is a complicated appliance that employs a switching power device designed for discharging and charging a capacitor to more than 1 kV. For a simple transcranial magnetic stimulation device, this study used commercial power and controlled the firing angle using a Triac power device. AC 220V 60 Hz, the power device was used directly on the tanscranial magnetic stimulation device. The power supply device does not require a current limiting resistance in the rectifying device, energy storage capacitor or discharge circuit. To control the output power of the tanscranial magnetic stimulation device, the pulse repetition rate was regulated at 60 Hz. The change trigger of the Triac gate could be varied from $45^{\circ}$ to $135^{\circ}$. The AVR 182 (Zero Cross Detector) Chip and AVR one chip microprocessor could control the gate signal of the Triac precisely. The stimulation frequency of 50 Hz could be implemented when the initial charging voltage Vi was 1,000 V. The amplitude, pulse duration, frequency stimulation, train duration and power consumption was 0.1-2.2T, $250{\sim}300{\mu}s$, 0.1-60 Hz, 1-100 Sec and < 1 kW, respectively. Based on the results of this study, TMS can be an effective method of treating dysfunction and improving function of brain cells in brain damage caused by ischemia.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.20-29
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• 2018

The dynamic characteristics of power systems become more and more complex because of the integration of large-scale wind power, which needs appropriate control strategy to guarantee stable operation. With wide area measurement system(WAMS) creating conditions for realizing realt-ime transient stability analysis, a new coordinated control strategy for power system transient stability control based on phase-plane trajectory was proposed. When the outputs of the wind farms change, the proposed control method is capable of selecting optimal generators to balance the deviation of wind power and prevent transient instability. With small disturbance on the base operating point, the coordinated sensitivity of each synchronous generator is obtained. Then the priority matrix can be formed by sorting the coordinated sensitivity in ascending order. Based on the real-time output change of wind farm, coordinated generators can be selected to accomplish the coordinated control with wind farms. The results in New England 10-genrator 39-bus system validate the effectiveness and superiority of the proposed coordinated control strategy.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.4
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• pp.159-164
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• 2005

Various compensators are installed into the power system to operate the system economically and stably by maximizing the availability of utilities and power transmission capability. Fixed Capacitor(FC), Mechanical Switched Capacitor(MSC), and FACTS(Flexible AC Transmission Systems) are used to regulate voltage and power flow of the system. When a disturbance occurs in the power system, the Fixed Capacitor operates dependently on the voltage of the power system and cannot change the amount of installation automatically. But compared to other equipment, the Fixed Capacitor is more economical due to its low cost. Since MSC can change the amount of installation according to the state of the power system, operates more effectively than the Fixed Capacitor. FACTS have fast dynamic performance for the transient condition, but the cost is high. Therefore, it is needed to develop an optimized installation planning for the reactive power compensators by considering their dynamic performance and cost. In this paper, an optimized compensator combination and the proposed scheme is proposed and it is applied to KEPCO system in order to show its capabilities.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.4
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• pp.484-498
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• 2022

The purpose of this study is to analyze the location, distribution and its change of photovoltaic power generation in the scale of municipality(Si-Gun-Gu). First the distribution of photovoltaic power generation was analyzed in 2020, and second, from 2017 to 2021, we tracked the increase in capacity of power generation facilities in each Si-Gun-Gu. As a result, the distribution and increase of photovoltaic power generation were concentrated in some regions and the unequal distribution of photovoltaic power generation has been identified through Gini coefficient.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.spc1
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• pp.97-107
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• 2024

Efforts to respond to climate change are being made in various ways around the world, and in the energy field, continuous research and pilot projects are underway through new and renewable energy, efficient power grid management, and power grid services. Systems are in place to realize these efforts, and the systems created allow for better effectiveness. When implementing a system, systems engineering methodology helps design a more systematic system and can provide verification accuracy and uniformity through intuitive connectivity. In this paper, the original requirements of the power grid stabilization system and the architecture of the system's essential constraints are constructed as a conceptual model and the boundaries and flows between components are defined. By utilizing distributed resources such as EV(Electric Vehicle) and ESS(Energy Storage System) in the power service platform system, we plan to design and build a next-generation power service system that can participate in the power stabilization market and implement a system necessary to respond to climate change in the future.

• Design & Manufacturing
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• v.2 no.3
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• pp.32-39
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• 2008

after using dom die, this sheet pressed from a variation condition of size, of die holder power,of rpm speed, accordingly the kind of material, the conditionof deformation movement between both sheets is analyzed, is investigated in the Press machine. even if the change quantity which formed raises a blank holder pressure, the change quantity which is special is not visible from the segment where there is not a bead, the segment where there is a bead to the other side does change quantity schedule to initially and the features of press holding power which the change quantity diminishes is showed consequently from pressurization change quantity it is visible but until a rupture territory from the rpm, it goes but the features where the change quantity does not change a lot is observationd, from the CR2-sheet the quality comes out though well but a possibility of getting a result under same conditions of AL-sheet does not become the formation which stands is. It is like that though press-die which uses the drawing-sheet it exchanges the sheets, when AL-sheet with doing, the conclusion for maintain which have a formation sincerity healthy characteristic is same with afterwords.