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Showing papers by "Robert J. Thomas published in 2006"


Journal ArticleDOI
30 Nov 2006
TL;DR: In this paper, a probabilistic reliability criterion is used to determine an optimum plan for transmission system expansion using a criterion that minimises the expected cost, which includes both construction and outage costs.
Abstract: Probabilistic reliability criteria, such as LOLP, LOLE, EENS etc., have been used extensively for generation expansion planning throughout the world. Typically, only deterministic reliability criteria, such as (N-1) or (N-2) contingencies, have been used for grid expansion planning until now. The main reason is the difficulty in determining the optimum design of a grid expansion plan using probabilistic reliability criteria and in developing the appropriate mathematical model that incorporates the chosen reliability criterion for the transmission system. Optimum design in grid expansion planning is still an important element of overall electric power system planning in deregulated electricity markets. One of the potential improvements in generation and grid expansion planning comes from the use of a more realistic reliability level as a criterion to constrain the form of the optimum expansion problem. A methodology is proposed that uses a probabilistic reliability criterion to determine an optimum plan for transmission system expansion using a criterion that minimises the expected cost, which includes both construction and outage costs, using a probabilistic reliability criterion loss of load expectation R LOLE. The optimum value of the reliability criterion R LOLE * is determined at the minimum value of the combined total of the cost of constructing new transmission and the customer outage cost associated with supply interruptions. The characteristics and effectiveness of this methodology are illustrated by a case study using a 21-busbar test system

63 citations


Proceedings ArticleDOI
04 Jan 2006
TL;DR: The method solves for the optimal strategy using a branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem and minimizes total investment cost.
Abstract: This paper proposes three methods for choosing the transmission system expansion plan considering three reliability constraints, which are deterministic reliability criterion, probabilistic reliability criterion and security criterion based on N-α contingency in order to give more successful market operation. The proposed method minimizes total investment cost It models the transmission system expansion problem as an integer programming one. The method solves for the optimal strategy using a branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. The 21 bus system case study results demonstrate that the proposed method is practical for solving the power system expansion planning problem subject to practical future uncertainties.

44 citations


Proceedings ArticleDOI
04 Jan 2006
TL;DR: Computational challenges for scaling the proposed revenue sensitivity-based approach for identifying market participants with market power potential to large systems are addressed, and practical extensions to the work are presented that enables the evaluation of very large, RTO-scale electric power grids.
Abstract: Market power potential is a serious concern for efficient and competitive operation of centrally-dispatched electricity markets. Traditional measures for market power ignore underlying physical characteristics of the electric grid that may be exploited for local advantage. In our prior work we have proposed a revenue sensitivity-based approach for identifying market participants with market power potential, and we demonstrated detailed cases using a 30-bus system[1] [2] [3]. In this paper we address computational challenges for scaling our method to large systems, and we present practical extensions to a portion of our work that enables the evaluation of very large, RTO-scale electric power grids.

17 citations


Proceedings ArticleDOI
01 Oct 2006
TL;DR: In this article, the authors proposed a probabilistic approach under security criterion constraint for choosing the best transmission system expansion plan considering expected stand-by cost based on probabilism approach.
Abstract: This paper proposes a methodology for choosing the best transmission system expansion plan considering expected stand-by cost based on probabilistic approach under security criterion constraint Long-term grid expansion planning problem includes many uncertainties of network The method in this paper describes a model of security probability considered stand-by cost of generators in objective function Security probability is defined as level of uncertainties of contingency elements Furthermore, the proposed method minimizes total cost including the investment cost as well as operating cost and probabilistic stand-by cost of generators for constructing new transmission lines subject to (N-alpha) contingency security criteria, which are essentially extended types of (N-1) contingency It models the transmission system expansion problem as an integer programming one The method solves for the optimal strategy using a branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem The fine characteristics are shown by the proposed method applied to the 5-bus system It demonstrates that the proposed method may become practical tool for solving the power system expansion planning problem

5 citations


01 Jan 2006
TL;DR: In this article, the authors proposed a methodology for choosing the best transmission system expansion plan considering expected stand-by cost based on probabilistic approach under security criterion constraint, which is defined as level of uncertainties of contingency elements.
Abstract: This paper proposes a methodology for choosing the best transmission system expansion plan considering expected stand-by cost based on probabilistic approach under security criterion constraint. Long-term grid expansion planning problem includes many uncertainties of network. The method in this paper describes a model of security probability considered stand-by cost of generators in objective function. Security probability is defined as level of uncertainties of contingency elements. Furthermore, the proposed method minimizes total cost including the investment cost as well as operating cost and probabilistic stand-by cost of generators for constructing new transmission lines subject to (N-�. ) contingency security criteria, which are essentially extended () ,

3 citations


Journal ArticleDOI
TL;DR: In this article, an agent based on a double-layer diffusion model developed elsewhere is tested and its effectiveness reported, suggesting that market participants will pursue their own profit-maximizing objective rather than use an objective that reflects social benefit.
Abstract: Worldwide energy markets have been on a path toward deregulation for several decades. These markets have proven to be difficult to design and run because of their repetitive nature and the externalities provided by reliable grid operation. In a deregulated market environment, our experiments suggest that market participants will pursue their own profit-maximizing objective rather than use an objective that reflects social benefit. Multiagent simulation is useful for gaining insights into market participant behavior under various rules. In this way, market rules can be tested for efficacy and efficiency. In this paper, an agent based on a double-layer diffusion model developed elsewhere is tested and its effectiveness reported

3 citations


Proceedings ArticleDOI
04 Jan 2006
TL;DR: In this paper demand is categorized into two groups: one that highly values reliability and the other that does not, and a new optimal bidding function is developed and tested based on this model.
Abstract: Problems such as price volatility have been observed in electric power markets. Demand-side participation is often offered as a potential solution by promising to increase market efficiency when hockey-stick type offer curves are present. However, individual end-consumer will surely value electricity differently, which makes demand-side participation as a group and at a bus difficult. In this paper demand is categorized into two groups: one that highly values reliability and the other that does not. The two types are modeled separately and a new optimal bidding function is developed and tested based on this model.

3 citations