Carlos M. V. Tahan

Daily load profiles for residential, commercial and industrial low voltage consumers

This paper presents the results of the study carried out for the determination of the residential, commercial and industrial consumers daily load curves based on field measurements performed by the Utilities of Electric Energy of Sao Paulo State, Brazil. A methodology for the aggregation of these loads to determine the expected loading in equipment of in a preset part of the distribution network by using the representative daily curves of each consumers activity and the monthly energy consumption of the connected consumers is also presented.

Distribution transformer loss of life evaluation: a novel approach based on daily load profiles

This work presents a methodology for distribution transformer rating selection and management. Measured or estimated daily load profiles are used to determine the transformers loss of life. Loss of life values are obtained for a number of transformers and are stored together with the corresponding load profiles in a database of patterns. The expected loss of life for a transformer not included in the database is obtained by comparing the transformers actual load profile to the ones stored in the database.

A model for electricity markets: The impact of regulation on value

In this paper it is proposed a simple, although useful model, intended for electricity markets, which enlightens the analysis of regulatory procedures and their consequences over value creation. Today it is widely recognized that, in regard to public services, the aim of regulation should be to maximize the social wealth added (EWA). This wealth includes consumers surplus (ECA), tributes paid to government (EGA) and investor value added (EVA). Thus, regulation implies both efficiency, regarding the location of resources, and fair price levels. The task is seriously impaired by informational asymmetries, and a second-best optimum is only attained with incentive-compatible contracts. Those problems, among many others, can be treated with the proposed model. In order to clarify some of the issues, an example is developed showing the social wealth added under several instances of market operation: regulates vs. unregulated firm, level of taxation, and optimized vs. non-optimized investment and resources.

Modeling the influence of power quality on the creation of market value

This paper deals with the modeling of electric markets whenever certain imperfections pollute the supplied electrical energy. These imperfections are described in terms of a lack in power quality, and must be quantitatively introduced in the model as an additional economic factor which influences the consumption of electrical energy and its market price. In the model of a commodity market, where electrical energy is an undifferentiated good, power quality - if it exists - is considered of no consequence on the economics of such market. This is not the case in practice: imperfections have indeed a notorious influence on the trade of electrical energy and their insertion in a market model is an urgent need. The model here proposed allows the analysis of such spurious conditions and to point out the optimum values to be attained either from the point of view of the utility or the public interest expressed across the incentive regulation of the market. Several examples illustrate the application of the model on the grounds of optimum investments and quality targets.

The influence of quality on the creation of economic value in electricity markets

This paper deals with the modeling of electric markets whenever certain imperfections pollute the supplied electrical energy. These imperfections are described in terms of a lack in power quality, and must be quantitatively introduced in the model as an additional economic factor which influences the consumption of electrical energy and its market price. Therefore, the main intent of this paper is to provide a unifying perspective in regard of the following question: How much the economic performance of electricity markets is downgraded by imperfections of supply? Such a problem can only be resolved with the aid of a market model, which should be able to integrate both technological and financial features in a single analytical frame. This is precisely the type of market model which is developed in the paper: a one including imperfections along with the other sources of cost. While very simple, the market model may be used in various important studies, such as the x-factor for productivity gains, quality target calculation, disturbances mitigation by demand-side management, etc‥ An application to compute continuity standards will be developed as an example of the model usage and potentiality.

The Impact of Power Quality on the Economy of Electricity Markets

1.1 Basic concepts The main goal of this chapter is the economic valuation and prioritization of those investments which are intended to improve the power quality of the system. While most of the research work in the field of power quality was aroused by the scientific challenges to be overcome, it is fair to recognize that the practical importance of power quality hinges on the economic impact of such phenomena. Thus, economic analysis of power quality is of the outmost significance. Such analysis, according to present day corporate doctrine, implies the assessment of the changes in the market value which are produced when an ideal scenario – where electric energy is supplied without any imperfection – is disturbed by a series of distortional events, thus leading to a loss of quality. In brief, we want to relate imperfection level with market value. In a more practical line of thought, we wish to answer specific questions like this: how many equivalent dollars of market value are lost when the severity index of some type of imperfection increases – say – by one unit? Or – opposingly – how many dollars are won because of a decrease in severity? Moreover, given an intervention in the markets which diminishes the index, we seek to estimate the monetary benefit of such quality improvement. As we also know the capital needed to accomplish such intervention we can introduce in the market model and the change in value added may be subsequently calculated. Then, the relation between that change and the capital invested can be compared against a hurdle rate which functions as a yardstick for the merit of the intervention. This can be used also in order to prioritize capital investments on power quality (this rather straight way of investment prioritization, becomes more complicated when the uncertainties inlaid in the quality issues are introduced).

Regulation of supply quality in open electricity markets

This paper addresses power quality (PQ) in view of regulation, i.e. the sets of rules contriving to optimal control of the market. The state of the market depends on: (1) investments; (2) consumers willingness; and (3) quality and price. The goal function is chosen as a net public welfare (W) arising from market transactions. (W) is expected to sway towards maximum by means of regulatory signals radiated whenever PQ fails to comply with elected standards. A linear model of an electricity market is devised, elucidating the main features of its optimal dynamic evolution. In order to illustrate the main points, Brazilian practices on reliability standards are succinctly described.

Economic impacts of the discontinuity of power services by using an electricity market model

This study focuses on obtaining the regulatory tariffs from a microeconomic point of view, through studies on the optimization of investments and cost minimization, and focus on the issue of compensation to the customer due to deficiencies in the quality of the supplied energy by using the TAROT (optimized tariff) model. The methodology of direct compensation to the customer aims to ensure that investments in power quality are not maid below the values which guarantees the continuity goals imposed by the regulatory agency, providing, in case of violation of the standards, an added value to the consumer close to that he would get with the target indexes. This methodology was applied in a Brazilian distribution company, and the resulting tariffs were compared against each other as well as the resulting aggregated economic values.

The X Factor and its economic and technical significance

This paper aims to determine regulatory tariffs using a Market Model in order to assess the profits arising either from technical innovation or management rationalization, in a balanced fashion among consumers and distribution companies, guaranteeing appropriate incentives. It is estimated that the paper contribution to further improve public policies affecting the electricity sector.

Proposal and comparative analysis of alternative methods on the definition of load curves typologies

The knowledge of the way consumers use the energy is necessary for many studies, either commercial or technical. This knowledge can be reached by obtaining the load curves from all the customers of the company. However, given the great number of necessary measurements, this practice is not viable. The alternative currently used for tariff reviews in Brazilian electrical system is based on the sampling theory associated with data analysis techniques. After obtaining the information, the load typologies that represent each transformer or customer are calculated through some stages of load characterization. The results obtained allow a more accurate analysis of the electric energy market and, specially, the knowledge of how each consumer class uses the electricity network. This research involves part of the previously mentioned study on the analysis of the data collected in the measurement campaign. It considers and evaluates alternative methodologies for two stages of the load typologies characterization process, the selection of typical curves and the data classification. These methodologies are adjusted to the necessities of the tariff reviews and on the basis of heuristical methods and electricity sector practices. After the development and implementation of the methodologies, tests have been carried out between the considered processes, comparing and evaluating their particularities through the similarity between the typologies found for transformers and consumers on the same tension level. The comparison of the performed analysis allowed the identification of the impacts and characteristics of the developed methodologies, for each studied stage.