• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.256-263
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• 2009

For the power system to keep in a stable operating state, sufficient ancillary services must be available to respond to credible contingency events and return the power system to a satisfactory operating state in the case of contingencies as well as blackout events within specified predefined limits. The logical and reasonable bases of valuing and pricing the ancillary services are required to reach the common ground among market participants. The total amount of black start service transactions is quite small compared to the total ancillary service transactions as well as energy market transactions. Black start services must be provided as one of the ancillary services in the deregulated electricity market. In order to procure and remunerate black start services, it is necessary to quantify the value of the black start sources within the power system. In this paper, an approach to assess the value of the black start service is presented based on the cost-of-service solution. Financial simulation of the influence on market participants for the proposed approach on the service is carried out. The cost of the black start service is allocated in accordance with the principle of "causer pays", and the cost is shared by the producers and consumers equally that created the requirement for the service. Under the present electricity market, the mechanism to recover the cost is not implemented, a new approach to the ancillary services to provide incentive for the service providers has to be studied in the near future.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.40-50
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• 2016

In order to recover the power system during the wide power outage or power failure in the power plant, black start system should be properly operated without any problem. Especially power for black start in the geographically isolated areas of electric island is supplied from small emergency start-up generator, and loads are aux systems of gas turbines such as SFC(Static frequency converter). This paper introduces the international practices to overcome the voltage drop problem with harmonics of the system having the DC output such as SFC during black start in weak feed system and analyzes the relationship between house load inputs and harmonics. By varying the house load and input of power supply, this paper identified boundaries between weak feed and strong feed power. In order to verify the theory of stable condition in weak feed power system with DC output, house load is simulated using ETAP. Additionally MATLAB was used for harmonic analysis between the load inertia moment and non load inertia moment.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.1-8
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• 2015

The purpose of this research is to identify the start and end point of TV program on Web TV. Until now, to replace realtime TV advertisement with Web TV advertisement, human work was the only way. To automatize the process, knowing the start and end point of TV program is the core technology. In this study, I extract 'Black level' between TV program and regard it as start & end point of program. The result of this study is showing that extracting 'Black level' can be a useful tool to define start & end point of TV program. And it will be also use an automatize replacement system for Web TV advertisement.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.7
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• pp.898-904
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• 2013

In order to minimize the damage from power outage, power system should be restored quickly. In this paper, a procedure for the restoration of microgrid is proposed. After elimination of the causes of power outage, a black start algorithm is executed by considering the characteristics of distributed generation control. After all resources have been recovered to the normal state, a grid reconnecting algorithm for stable operation in grid-connected mode is performed. In order to verify the proposed algorithm, low voltage microgrid is simulated using PSCAD/EMTDC.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.4
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• pp.191-198
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• 2019

The purpose of this study is to explain the bootstrapping method to understand the process of overcoming the difficulties experienced by the limited resources of the initial start-up, through the example of Black Ruby Studio. Most nascent start-ups have constrained resources. This problem is a subject that is constantly being repeated in entrepreneurship research. Despite these problems, there are relatively few studies detailing the process of overcoming the initial difficulties of start-up. Bootstrapping is described as a way to reduce external inflows, reduce risk, and resolve funding issues internally. Many start-ups initially rely on bootstrapping as a way to solving scarce funds and limited resources. Therefore, this study reviewed the prior literatures in bootstrapping, and used 32 detailed item bootstrapping methods suggested in Winborg & Landstrom(2001) on bootstrapping in order to understand bootstrapping concept of start-up. This study gives insightful implication to prospective founders by using the bootstrapping method for survival of start-up and the process of overcoming the difficulties in the start-up.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.30-37
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• 2018

Unlike an AC system, a DC system does not cause problems with synchronization, stability, reactive power, system losses, and cost. However, more research is still required for the application of DC Systems. This paper proposes a stable black-start strategy for a stand-alone DC micro-grid, which consists of an energy storage system, photovoltaic generator, wind-turbine generator, diesel generator, and DC loads. The proposed method is very important for avoiding inrush current and transient overvoltage in the power system equipment during restoration after a blackout. PSCAD/EMTDC software was used to simulate, analyze, and verify the method, which was found to be stable and applicable for a stand-alone DC micro-grid.

• KIPE Magazine
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• v.25 no.4
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• pp.50-55
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• 2020

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.14-17
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• 2007

Power system restoration following a massive blackout starts with re-energizing primary restorative transmission systems at first. The comparison of the TLCC(transmission line charging capacity) and the RPC(reactive power capability) of related black-start generator should be considered in this stage because overvoltage can be caused by self-excitation at the generator when the RPC is smaller than the TLCC. The RPC can be decided by two criteria. One is stator end core heating, and the other is steady state stability. RPC in steady state stability area has been found based on a synchronous reactance Xd. This paper presents RPC limit of salient pole machine which is different from that of non-salient pole machine in steady state stability area and shows derivation process about that.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.44-46
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• 2002

Service restoration following a complete or partial collapse starts with reenergize a transmission line from black-start generators. Voltage problems can arise by Ferranti effect as unloaded transmission line is reenergized. This paper presents analytical results on the primary restorative transmission system focused on the voltage problem during the early restoration process. Methodologies to handle load pick-up compensating Ferranti effect. and terminal voltage and reactive capability limitation of black-start generators about self-excitation are presented. An algorithm for static analysis about these methodologies is developed, and EMTDC simulation for verifying the efficiency of the algorithm is performed.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1377-1382
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• 2015

Power system restoration following a massive blackout starts with re-energizing Primary Restorative Transmission (PRT) systems at first. As power systems have been gradually enlarged and become more complex, periodical evaluation and reassignment of PRTs are needed. So far it has been decided by try and error approach by corresponding human experts to analyze and evaluate them. This paper presents an intelligent system that finds optimal primary restoration paths using analytic and heuristic knowledge from PSS/E data, and suggests an optimal PRTs depending on the condition of Ferranti effect or a reactive power capability margin of black-start generator. This system was tested in Korea Electric Power system, and showed a promising result.