Showing papers by "Robert J. Thomas published in 2003"

Locational pricing and scheduling for an integrated energy-reserve market

Abstract: It is well known that given a network that can become constrained on voltage or real power flows, reserves must also be spatially located in order to handle all credible contingencies. However, to date, there is no credible science-based method for assigning and pricing reserves in this way. Presented in this paper is a new scheduling algorithm incorporating constraints imposed by grid security considerations, which include one base case (intact system) and a list of possible contingencies (line-out, unit-lost, and load-growth) of the system. By following a cost-minimizing co-optimization procedure, both power and reserve are allocated spatially for the combined energy and reserve markets. With the Lagrange multipliers (dual variables) obtained, the scheduling algorithm also reveals the locational shadow prices for the reserve and energy requirements. Unlike other pricing and scheduling methods in use, which are usually ad-hoc and are based on engineering judgment and experience, this proposed formulation is likely to perform better in restructured markets when market power is a potential problem. An illustrative example of a modified IEEE 30-bus system is used to introduce concepts and present results.

A revenue sensitivity approach for the identification and quantification of market power in electric energy markets

Abstract: In this paper we present a practical approach for identifying and measuring market power in an electric energy market. To do so we determine which participants or groups of participants have the ability to increase their own revenues without affecting the rest of the market, and then apply a relative measure to quantify the extent of market power exploitation. We present a 30-bus, 6-generator example in which two generators in a load pocket are found to have and use market power. Using price and revenue signals from a repeated auction, we explain how these generators learn to exploit their power over time. Experimental results are also presented and analyzed.

Bluenet II - a detailed realization of the algorithm and performance analysis

Abstract: The recent interest in ad hoc networks, in general, and in the Bluetooth technology, in particular, has stimulated much research in algorithms for topology control of such networks. In particular, the issue of scatternet formation has been addressed by a number of papers in the technical literature. In (Wang et al., 2002), we have proposed one such algorithm called the Bluenet algorithm. In this paper, we further investigate the realization and properties of the Bluenets algorithm. The performance of the resulting scatternets, such as, piconet density, usage of potential links, deviation of node degrees, average shortest path length, and maximum traffic flows are also studied. From the analysis, it is showed that the choice of p/sub 0/, the initial probability for each node to enter the page state, is very important. Since each performance index only reflects one side of the scatternet performance, we need to make trade offs when selecting p/sub 0/ to build Bluenets.

Comparing the behavior of agents to human subjects in a uniform price auction

Abstract: The idea that large-scale generating units operates at marginal cost when given the ability to offer their power for sale in a uniform price auction is at best wishful thinking. In fact, both real and experimental data show that the more uncertainty a supplier faces (e.g., load uncertainty, uncertainty of other suppliers, etc.) the more they try to increase their profits by submitting offers to sell higher than marginal cost and by withholding units if permitted. This makes predicting unit commitment and dispatch ahead of time difficult. This paper explores characteristics of software agents that were designed based on the outcome of tests with human subjects using a uniform price auction with stochastic load. The agent behavior is compared to the behavior of the subjects. Both subject and agent behavior is classified based on the data. Differences and similarities are noted and explained.

Bluenet II -- A Detailed Realization of the Algorithm and Performance

Abstract: The recent interest in ad hoc networks, in general,and in the Bluetooth technology, in particular, hasstimulated much research in algorithms for topologycontrol of such networks. In particular, the issue ofscatternet formation has been addressed by a number ofpapers in the technical literature. In [1], we haveproposed one such algorithm called the Bluenetalgorithm. In this paper, we further investigate therealization and properties of the Bluenets algorithm. Theperformance of the resulting scatternets, such as, piconetdensity, usage of potential links, deviation of nodedegrees, average shortest path length, and maximumtraffic flows are also studied. From the analysis, it isshowed that the choice of 0 p , the initial probability foreach node to enter the page state, is very important.Since each performance index only reflects one side ofthe scatternet performance, we need to make trade offswhen selecting 0 p to build Bluenets.