• 전기학회논문지
• /
• 제62권4호
• /
• pp.457-466
• /
• 2013

Wind energy is rapidly becoming significant generating technologies in electricity markets. As probabilistic nature of wind energy creates many uncertainties in the short-term scheduling, additional actions for reliable market operation should be taken. This paper presents a novel approach to evaluate ramping capability requirement for changes in imbalance energy between day-ahead market and real-time market due to uncertainty of wind generation as well as system load. Dynamic ramp rate model has been applied for realistic solution in unit commitment problem, which is implemented in day-ahead market. Probabilistic optimal power flow has been used to verify ramping capability determined by the proposed method is reasonable in economic and reliable aspects. This approach was tested on six-bus system and IEEE 118-bus system with a wind farm. The results show that the proposed approach provides ramping capability information to meet both forecasted variability and desired confidence level of anticipated uncertainty.

• KDI Journal of Economic Policy
• /
• 제31권2호
• /
• pp.87-126
• /
• 2009

인터넷포털 산업에서 최종사용자시장으로부터 광고주시장으로 작용하는 간접 네트워크 외부성과 최종사용자시장 내의 직접 네트워크 외부성의 크기는 인터넷포털 기업 간 경쟁에 있어서 중요한 경쟁정책적 의미를 가진다. 본 연구는 국내 인터넷포털 산업에서 직 간접 네트워크 외부성의 실재와 크기, 인터넷포털 기업들의 시장력을 실증구조모형을 통해 분석하고 경쟁정책에의 시사점을 제시한다. 본 연구의 분석 결과는 산업 내에 이러한 직 간접 네트워크 외부성이 실재하며, 이로 인해 최종사용자시장 점유율과 광고주시장의 시장력 사이에 '레버리지' 효과가 존재함을 보여준다.

• Journal of Electrical Engineering and Technology
• /
• 제8권4호
• /
• pp.667-674
• /
• 2013

Wind power producers face many regulation costs in deregulated environment, which remarkably lowers the value of wind power in comparison with conventional sources. One of these costs is associated with the real-time variation of power output and being paid in frequency control market according to the variation band. This paper presents a new approach to coordination of battery energy storage in wind generation system for reducing the payment in frequency control market. The approach depends on the statistic data of wind generation and the prediction of frequency control market price to determine the optimal variation band which is then kept by the real-time charging and discharging of batteries, ultimately the minimum cost of frequency regulation can be obtained. The optimization problem is formulated as trade-off between the decrease in the regulation payment and the increase in the cost of using battery, and vice versus. The approach is applied to a study case and the results of simulation show its effectiveness.

• KEPCO Journal on Electric Power and Energy
• /
• 제2권1호
• /
• pp.133-141
• /
• 2016

비록 미국에서는 1970년대 중반부터 최근까지 신규 원전프로젝트 건설이 없었지만, 여러 국가에서 주로 에너지 시큐리티와 전력에너지원 다변화 정책의 일환으로 원전의 신규건설이 지속되어 왔다. 금세기 초부터 여러 가지 이유로 원자력 산업은 재부흥이 일어나고 있는 양상이었고, 원전 프로젝트에 대한 투자에 있어서도 민간 금융부문로부터 긍정적인 관심을 불러 일으켰다. 하지만 2008년도의 세계적 금융위기와 이후 이어진 경제발전 둔화는 금융규제와 더불어 주요 파이낸싱의 원천인 상업은행들의 원전 프로젝트에 대한 의욕을 상실케 했다. 반면 원자력 발전의 경제성은 환경적 이득 측면과 비용측면에서 타 전원대비 유리하다는 것을 보여준다. 그리고 기술발전과 강화된 안전관련검사 및 모니터링은 원전의 안전성에 대한 의구심을 많이 완화시켰다. 따라서 원전 시장의 향후 확산에 대한 전망은 상이한 가정별로 비교적 큰 차이가 있지만 긍정적인 편이다. 2009년 12월 한국전력이 UAE원전을 수주하면서부터 원전시장에서의 경쟁은 큰 변화를 겪고 있다. 많은 경쟁자들이 정부의 지원을 등에 업고 새로운 원전 프로젝트를 수주하기 위해 공격적이고 새로운 파이낸싱 패키지를 가지고 시장에 진출하고 있다. 본 논문은 신규원전 시장의 전망, 원전의 상대적 경쟁력, 리스크 관리방안, 파이낸싱의 과제들을 분석하고 신규원전 수주 경쟁력 제고를 위한 대안들을 제시하고자 한다.

• 대한전기학회논문지:전력기술부문A
• /
• 제52권7호
• /
• pp.429-436
• /
• 2003

This paper presents a new approach for evaluating the transmission marginal loss factors (MLFs) considering the reactive power. Generally, MLFs are represented as the sensitivity of transmission losses, which is computed from the change of the generation at reference bus by the change of the load at the arbitrary bus-i. The conventional evaluation method for MLFs uses the only H matrix, which is a part of jacobian matrix. Therefore, the MLFs computed by the existing method, don't consider the effect of the reactive power, although the transmission losses are a function of the reactive power as well as the active power. To compensate the limits of the existing method for evaluating MLFs, the power factor at the bus-i is introduced for reflecting the effect of the reactive power in the evaluation method of the MLFs. Also, MLFs calculated by the developed method are applied to energy spot markets to reflect the impacts of reactive power. This method is tested with the sample system with 5-bus, and analyzed how much MLFs have an effect on the bidding/offer price, market clearing price(MCP), and settlement in the competitive energy spot market. This paper compared the results of MLFs calculated by the existing and proposed method for the IEEE 14-bus system, and the KEPCO system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
• /
• pp.177-179
• /
• 2005

In Korean Power Market, Cost-based Bidding Pool is maintaining the present condition because restructuring of electricity industry is holding. When this market is designed, Settlement rules for Pumped-storage power plant made unfairly by other power plants. These rules were considered contribution of Pumped-storage power plant to network operation. by the way, there are some discussion about Settlement rules modification. so in this paper, we calculated financial effect of power plant by modified rules. And when we modify market rules, we can offer numerical information.

• 대한전기학회논문지:전력기술부문A
• /
• 제49권6호
• /
• pp.266-271
• /
• 2000

The electric power industries are moving from the conventional monopolistic or vertically integrated environments to deregulated and competitive environments, where each participant is concerned with profit maximization rather than system-wide costs minimization. Consequently, the conventional least-cost approaches for the generation resource schedule can not exactly handle real-world situations. This paper presents a game theory application for analyzing power transactions and market design in a deregulated energy marketplace, where the market participants determine the net profits through the optimal bidding strategies. The demand elasticity of the energy price is considered for the realistic modeling of the deregulated marketplace.

• 국제학술발표논문집
• /
• The 2th International Conference on Construction Engineering and Project Management
• /
• pp.196-205
• /
• 2007

China power market is fast changing. The strong economic growth does make BOT power projects to be one of the focuses for investment in China due to the huge demand for energy by the Chinese government. Since late 80's,various power projects BOT studies have been carried out but appear too fragmented which fail to linked the BOT studies to the most recent government policies' changes or market movement. This study has carried out analysis on the recent changes in China power industry reform and local government authority empowerment. The impact of those changes to BOT investment has been identified and recommendations have been made on the new opportunities and new strategies especially from the Singapore's investors' point of view. A case study on BOT hydropower plant has been presented which could be a suitable model for Singapore investors.

• KIEE International Transactions on Power Engineering
• /
• 제11A권4호
• /
• pp.39-44
• /
• 2001

As electric power systems have been moving from vertically integrated utilities to a deregulated environment, the charging of reactive power management is a new challenging them for market operators. This paper proposes a new methodology to compute the costs of providing reactive power management service in a competitive electrical power market. The proposed formulation, which is basically different from those shown in the literature, consists of two parts. One is to recover investment capital costs of reactive power supporting equipment based on a reactive power flow tracing algorithm. The other is to recover operational costs based on variable spot prices using the optimal power flow algorithm. The charging shapes resulted from the proposed approach exhibit a quite good meaning viewed from a practical sense. It turns out that reactive power charged are mostly due to recovery of capital costs and slightly due to recovery of operational costs. The methods can be useful in providing additional insight into power system operation and can be used to determined tariffs of a reactive power management service.

• 한국의류학회지
• /
• 제26권5호
• /
• pp.606-617
• /
• 2002

The purpose of this study is to develop a decision model that helps manufacturers and retailers determine the optimal timing of markdown in order to maximize their profit. An optimal timing decision model was developed based on three steps; conjoint measurement, scenario analysis and simulation. Data were collected from the sample of 149 out of 170 undergraduate and graduate students in Seoul in 1997. From the Jeans market, 8 brands; Levi's, lee, Guess, Calvin Klein, Pintos, Get used, MFG, and Basic, were selected as competitors for this study. In the conjoint measurement, respondents estimated the level of preference, from 1 to 100, for each item in which brand, price, style, and colors were used to explain product characteristics. Then, in order to reflect competitive situation in Jeans market, four types of scenarios were developed. In each scenario, simulations were applied to decide optimal timing of markdowns that leads to maximal profitability and sales volume. The profit was calculated based on the equation; Profit = Jean's market volume x market share of each brand - cost, where market volume was obtained by integral calculus for market utility function, and market share by logit value of part-worth from the conjoint analysis. For the purpose of the parsimony of the research, costs and the level of markdown were fixed to 30% of the regular price. In results, the optimal timing decision model identified 3 different types of brands. The brands that do not need to take markdown were Ievi's, MFG, and Basic Jeans characterized by the highest brand power and the highest price zone. The brands that needed to take early markdowns were Guess, Lee, Calvin Klein, and Get Used with the intermediate level of brand power and price. The brand that need late markdown was Pintos with the weakest brand power among the competitors and the lowest price. The optimal range of markdown remains for further research.