• Title/Summary/Keyword: Generation Dispatch

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A Study of Unit Commitment Considering Environmental Effects by Fuel Substitution

  • Lee, Buhm;Kim, Yong-Ha;Park, Nam-Sup
    • Journal of information and communication convergence engineering
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    • v.1 no.2
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    • pp.93-97
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    • 2003
  • This paper proposes a new generation scheduling algorithm which can consider total quantity of contamination and energy limits based on Lagrangian Relaxation. First, we formulate a Lagrangian function which consider quantity of contamination including substitution of fuel, and quantity of fuel. Second, we developed Multi-state S.U.D.P. which can treat multiple fuels. Third, we propose an effective generation scheduling algorithm including Multi-state S.U.D.P.. As a results, unit commitment and generating power can be obtained to meet the environmental and fuel constraints with fuel substitution. By applying it to the test system, effectiveness of the method is verified.

Stochastic Analysis of the Uncertain Hourly Load Demand Applying to Unit Commitment Problem (발전기 기동정지 계획에 적용되는 불확실한 부하곡선에 대한 통계적 분석)

  • Jung, Choon-Sik;Park, Jeong-Do;Kook, Hyun-Jong;Moon, Young-Hyun
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.337-340
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    • 2000
  • In this paper, the effects of the uncertain hourly load demand are stochastically analyzed especially by the consideration of the average over generation of the Unit Commitment(UC) results. In order to minimize the effects of the actual load profile change, a new UC algorithm is proposed. The proposed algorithm calculates the UC results with the lower load level than the one generated by the conventional load forecast. In case of the worse load forecast, the deviation of the conventional UC solution can be overcome with the lower load level and the more hourly reserve requirements. The proposed method is tested with sample systems, which shows that the proposed method can be used as the basic guideline for selecting the potimal load forecast applying to UC problem.

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Economic Generation Allocation with Power Equation Constraints (모선 전력방정식을 제약조건으로 하는 경제적 발전력 연산방법)

  • Eom, Jae-Seon;Kim, Geon-Jung;Lee, Sang-Jung;Choe, Jang-Heum
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.8
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    • pp.398-402
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    • 2002
  • The ELD computation has been based upon the so-called B-coefficient which uses a quadratic approximation of system loss as a function of generation output. Direct derivation of system loss sensitivity based on the Jacobian-based method was developed in early 1970s', which could eliminate the dependence upon the approximate loss formula. However, both the B-coefficient and the Jacobian-based method require a complicated Procedure for calculating the system loss sensitivity included in the constraints of the optimization problem. In this paper, an ELD formulation in which only the bus power equations are defined as the constraints has been introduced. Derivation of the partial derivatives of the system loss with respect to the generator output and calculation of the penalty factors for individual generators are not required anymore in proposed method. A comprehensive solution procedure including calculation of the Jacobians and Hessians of the formulation has been presented in detail. Proposed ELD formulation has been tested on a sample system and the simulation indicated a satisfactory result.

Impact of Carbon Costs on Wholesale Electricity Market (탄소비용이 CBP전력시장에 미치는 영향)

  • Kim, Wook;Park, Jong-Bae;Lee, Joo-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.4
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    • pp.700-706
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    • 2010
  • Carbon costs, either in the form of a carbon tax or through permit prices in an emissions trading scheme, would ultimately be reflected in higher electricity prices. This price "pass-through" is very critical to the effective design of new policies to curb the amount of carbon emissions. This paper sets out in a structured way the factors that determine price pass-through and how carbon costs would impact on the electricity market and the existing coal-fired power plants. It is shown that pass-through can vary drastically if the underlying dispatch potential of generators varies significantly across alternative emissions reduction scenarios. It can also vary depending on the availability of competing cleaner forms of generation. Pass-through as a measure of business performance is therefore hard to generalize across different circumstances and should be interpreted carefully.

Improved Pre-prepared Power Demand Table and Muller's Method to Solve the Profit Based Unit Commitment Problem

  • Chandram, K.;Subrahmanyam, N.;Sydulu, M.
    • Journal of Electrical Engineering and Technology
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    • v.4 no.2
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    • pp.159-167
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    • 2009
  • This paper presents the Improved Pre-prepared Power Demand (IPPD) table and Muller's method as a means of solving the Profit Based Unit Commitment (PBUC) problem. In a deregulated environment, generation companies (GENCOs) schedule their generators to maximize profits rather than to satisfy power demand. The PBUC problem is solved by the proposed approach in two stages. Initially, information concerning committed units is obtained by the IPPD table and then the subprob-lem of Economic Dispatch (ED) is solved using Muller's method. The proposed approach has been tested on a power system with 3 and 10 generating units. Simulation results of the proposed approach have been compared with existing methods and also with traditional unit commitment. It is observed from the simulation results that the proposed algorithm provides maximum profit with less computational time compared to existing methods.

Bidding Strategies with the Opportunity Cost of Reactive Power in a Competitive Market (무효전력 기회비용을 반영한 전력시장 입찰전략 연구)

  • 이광호
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.1
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    • pp.67-72
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    • 2004
  • This paper addresses the bidding strategies of generating firms in a competitive market where the firms are provided with payment for generating reactive power. Reactive support for voltage control is an integral and critical part of power system operations. Since reactive support is unbundled in a competitive market under open access transmission, it is treated as one of ancillary services. The operation costs and opportunity costs for reactive support are compensated by payment to the firms, hence their bidding strategies will be affected. The opportunity costs are evaluated from the foregone profits of a generator in making sales in real power market by providing reactive support instead of real power. Game theory approach is used to analysis the transaction strategies of real power by the bimatrix method in this paper. Through computing the Nash equilibrium in a sample system, an incentive of a generator for improving the reactive generating capacity is found to be effective and the variations of the profits are analyzed as the demand power factor changes.

Analysis on a Generation Competition with Take-Or-Pay Contract in an Electricy Market (연료제약 발전기의 강제인수 조건이 반영된 전력거래 해석)

  • Lee Kwang Ho;Cho Cheol Hee;Shin Jae Hong
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.716-718
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    • 2004
  • This paper presents a formulation and a solution method for the optimization problem with a fuel constraint in a competitive electricity market. Take-or-Pay (TOP) contract for an energy resource is the typical constraint as a limiting factor. Two approaches are proposed in this paper for modeling the dispatch calculation in a market mechanism. The approaches differ in the subject who considers and inserts the fuel-constraint into its optimization problem. Market operator and each power producer having a TOP contract are assumed as such subjects.

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Analysis on Characteristics of Transmission Loss using Marginal Loss Factors Based on the KEPCO's Expected Peak Load Data of Year 2000 (한계손실계수에 의한 한전 예상첨두계통 송전손실 특성 분석)

  • NamKung, Jae-Yong;Choe, Heung-Gwan;Mun, Yeong-Hwan;O, Tae-Gyu;Im, Seong-Hwang;Han, Yong-Hui
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.50 no.7
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    • pp.333-339
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    • 2001
  • The transmission networks are not perfect conductors and a percentage of the power generated is therefore lost before it reaches the loads. This network loss effects to the cost of suppling power to consumers, and must be considered if the most efficient dispatch and location of generators and loads is to be achieved. In this paper, we propose an approximate calculation of marginal loss factors to analyze characteristics of transmission loss of KEPCO power system. These static marginal loss factors are approximately calculated based on the KEPCO's expected summer peak load data of year 2000.

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A Cooperative Game Embedding Transmission Pricing in the Competitive Electricity Market (송전요금을 고려한 게임이론적 전력거래분석)

  • Kang, Dong-Joo;Kim, Bal-Ho
    • Proceedings of the KIEE Conference
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    • 2000.11a
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    • pp.3-5
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    • 2000
  • It has been the paradigm of game theory that more than two utilities compete and determine the price and amount of dispatch. In order for this theory to be available on real power system, it is necessary to consider the transmission costs as well as the generation costs. In addition Independent System Operator(ISO) should be able to mitigate the congestion, recover the transmission costs and provide information for long-term capacity investment by devising reasonable pricing schemes for the transmission services. Generators also have to take the transmission costs into account when building the bidding strategies. This paper proposes an approach to analyzing the profit maximizing game considering the transmission cost in a competitive electricity market.

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Development of heuristic method for job shop scheduling with alternative machines (대안기계를 갖는 Jop Shop scheduling을 위한 발견적기법의 개발)

  • 최동순;정병희
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1996.10a
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    • pp.303-306
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    • 1996
  • This paper proposes a heuristic method for job shop scheduling with alternative machines. Our heuristic suggests four machine-selecting rules and two priority dispatching rules for modifying existent ones considering alternative machines, and then it extends existing nondelay/active job shop schedule generation. This heuristic provides good criteria(rules) in the selection of a proper machine among those performing a specific operation and for the dispatch of an operation to a selected machine and thus these rules permit the efficient job shop scheduling with alternative machines. The performances of our four machine-selecting rules in addition to the two priority dispatching rules, applied together with the existing 17 rules, are experimented and evaluated, respectively.

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