Continuing trend towards deregulation and unbundling of transmission services has resulted in the need to assess what the impact of a particular generator or load is on the power system. A new method of tracing the flow of electricity in meshed electrical networks is proposed which may be applied to both real and reactive power flows. The method allows assessment of how much of the real and reactive power output from a particular station goes to a particular load. It also allows the assessment of contributions of individual generators (or loads) to individual line flows. A loss-apportioning algorithm has also been introduced which allows the break down of the total transmission loss into components to be allocated to individual loads or generators. The method can be useful in providing additional insight into power system operation and can be used to modify existing tariffs of charging for transmission loss, reactive power and transmission services.

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Tracing the flow of electricity

This paper introduces a simple novel method of transmission supplement charge allocation based on topological analysis of power flows in the network. The method uses the MW-MILE methodology but analyses the share, not the impact of, individual loads and generators in line flows. This results in positive contributions from all the users hence rescinding the problem of counterflows.

Topological generation and load distribution factors for supplement charge allocation in transmission open access

The application of marginal costing to transmission pricing in open access schemes requires the collection of a supplement to finance the transmission systems. The paper describes the application of marginal cost based pricing in the Chilean power system and the difficulties faced in allocating the supplement among parties involved. Alternative methods for defining the allocation are formulated. Generalized generation and load distribution factors for cost allocation are formulated and implemented. The methods are applied to allocate payments for transmission services provided by the transmission network and by a distribution company. >

Marginal pricing and supplement cost allocation in transmission open access

In this paper, the authors describe the basic technical concepts involved in developing cost based transmission prices. They introduce the concepts of transmission pricing paradigms and methodologies to better illustrate how transmission costs are transformed into transmission prices. They also briefly discuss the role of these paradigms and methodologies in promoting "economic efficiency" which is narrowly defined in this paper. They conclude the paper with an example of the application of some of these paradigms and methodologies for pricing transmission services in Brazil.

Some fundamental, technical concepts about cost based transmission pricing

This paper presents an overview of usage-based methods of transmission cost allocation under open access. Allocation of transmission costs involves both technical and regulatory issues, and as a result, the methods available in the literature differ in their definition and measure of the "extent of use" of transmission resources. The primary objective of this paper is to provide a summary of techniques used for designing fair and equitable access fees for the recovery of fixed transmission costs. The discussion is thus organized under two major subtopics: algorithms for transmission usage evaluation and alternative pricing strategies. Numerical examples are provided to show the results using different methods.

Review of usage-based transmission cost allocation methods under open access

The authors describe the principles and the implementation of a methodology to evaluate the transmission network capacity use for firm transmission services including wheeling transactions. In this methodology, transmission network capacity use of a transaction is a function of the magnitude of electric power, the length of the transmission lines, and the type of facility involved in the transaction. This capacity value provides an equitable means of allocating the cost of transmission facilities among users of the firm transmission service. Through examples, it is shown that this methodology, called the MW-mile methodology, is more reflective of the actual usage of the transmission network in allocating the transmission network capacity cost than the now widely used postage stamp rate procedure. Also indicated is the potential for realizing greater economic efficiencies through the use of this methodology. >

Eric T. K. Law

Papers

Evaluation of transmission network capacity use for wheeling transactions