• 전기학회논문지
• /
• 제58권2호
• /
• pp.256-263
• /
• 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.

• 전기학회논문지
• /
• 제65권1호
• /
• pp.40-50
• /
• 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.

• 한국콘텐츠학회논문지
• /
• 제15권1호
• /
• pp.1-8
• /
• 2015

본 논문은 웹TV에서 방송프로그램의 시작과 종료의 인지에 대한 연구이다. 현재 웹TV 서비스를 위하여 VOD 파일을 생성하고, 실시간방송의 광고를 웹TV용 광고로 교체하기 위해 수동적인 방법을 이용하고 있다. 이를 자동화하기 위해서는 방송프로그램의 시작과 종료 지점을 인지해야 한다. 본 논문에서는 실시간으로 프로그램과 프로그램 사이에 발생하는 흑 레벨(Black Level)을 검출하여 방송 프로그램 시작과 종료 지점으로 인지하여, 방송프로그램의 시작과 종료 신호를 발생하여 자동으로 VOD 파일을 생성하고, 웹TV용 광고로 교체할 수 있는 기법을 제안한다.

• 전기학회논문지
• /
• 제62권7호
• /
• pp.898-904
• /
• 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.

• 벤처창업연구
• /
• 제14권4호
• /
• pp.191-198
• /
• 2019

본 연구는 초기 스타트업의 제한된 자원으로 겪게 되는 어려움을 극복하는 과정을 이해하기 위해 부트스트래핑(bootstrapping)방법을 적용하여, 한양대학교 학생창업 기업인 (주)블랙루비 스튜디오의 사례를 통해 설명하고자 하였다. 스타트업 초기 겪게 되는 자원 조달에 대한 문제는 끊임없이 반복되어 오고 있는 연구 주제이다. 이와 같은 문제에도 불구하고 창업 관련 연구 분야에서 스타트업의 초기 어려움을 극복하는 과정을 자세히 설명하는 연구들은 비교적 많지 않다. 스타트업들은 창업을 시작할 때, 부족한 자금과 제한된 자원을 해결하기 위한 방법으로 외부의 자금 유입을 줄여 위험을 감소시키고 내부적으로 자금 문제를 해결하는 방법인 부트스트래핑에 의존하게 된다. 따라서, 본 연구에서는 스타트업의 부트스트래핑 개념을 이해하기 위해 관련된 선행연구 검토와 부트스트래핑에 관한 Winborg & Landstrom(2001)의 연구에서 제시된 32개의 세부적인 항목별 부트스트래핑 방법을 바탕으로 블랙루비 스튜디오의 창업자인 소재우 대표와의 수 차례의 심층 인터뷰를 통해 스타트업의 생존을 위한 부트스트래핑 방법 활용과 창업 초기 어려움을 극복하는 과정을 면밀히 분석하여 예비창업자들에게 통찰력 있는 시사점을 전한다.

• Journal of Electrical Engineering and Technology
• /
• 제13권1호
• /
• pp.30-37
• /
• 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.

• 전력전자학회지
• /
• 제25권4호
• /
• pp.50-55
• /
• 2020

• 전기학회논문지
• /
• 제56권1호
• /
• pp.14-17
• /
• 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.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 A
• /
• pp.44-46
• /
• 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
• /
• 제10권3호
• /
• pp.1377-1382
• /
• 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.