Marcos Roberto Gouvea

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.

Voltage regulation in electric energy distribution substations

This paper presents a comparative analysis among the various methodologies of automatic voltage control in electric power distribution substations, by studying the behavior of the steady state voltage. This project was based on a real case study in which three different voltage regulation techniques (Constant Voltage, Load Line, and Line Drop Compensation (LDC)) were implemented in a substation of a Brazilian utility of electric energy distribution. Measurements were performed at various points across one of the distribution feeders belonging to this substation. The comparative study among the methodologies took into account the local regulations, in special, the chapter 8 of the Procedures of Power Distribution of the National Electric System (PRODIST). The advantages and drawbacks of each methodology discussed in this paper are grounded in practical experiments in the real system. Studies and analysis suitable for each distribution system typology and load will allow, in the near future, the use and dynamic adjustment through a control center. Also, the use of Artificial Intelligence techniques will allow, in real time, the choice of the more appropriate regulation methodology for each case, using smart grid technologies.

A methodology for reclosers allocation in distribution networks

This paper presents a methodology that defines the most suitable configurations to allocate reclosers in power distribution networks. The methodology is composed by two stages. At the first stage, optimal configurations to install reclosers in each feeder are established, considering the improvement promoted in continuity indexes. Each configuration corresponds to a previously fixed number of reclosers and indicates the positions where the devices should be installed. So, through this stage, a list of possible optimal configurations is determined for each feeder. At the second stage a global optimization is carried out, in order to define which configuration should be considered in each feeder from a whole power distribution system, in order to maximize the improvement in terms of continuity and considering the total number of devices available. The developments presented are the initial part of a R&D project in progress with CEMIG-D, a power distribution company from Brazil.

Time Series modelling for solar irradiance estimation in northeast Brazil

In this work we used time series modelling for generating synthetic sets of hourly solar irradiance for the city of Petrolina located in the northeastern region of Brazil. The models were obtained for each month and were based on 20 years of satellite data. For each month, four time series structures were investigated: auto regressive, auto regressive integrated, auto regressive moving average and auto regressive integrated moving average. We compare the 48 obtained models by comparing the the mean of the synthetic series with the data set means. Another comparison made to validate the time series model was the square error between the data histogram and the synthetic series histogram. Results show that the different model structures generate the best fitting synthetic data for the studied city. This work describes the process of pre-filtering of the data for finally obtaining the monthly models. It also presents the generated synthetic series for hourly solar irradiation. The process described in this work might be used in the planning phase of a solar farm by generating stochastic data for solar irradiance estimation.

A Portable Voltage Regulator as an innovative smart grid solution

This article focuses on the developing of a Portable Voltage Regulator for Low Voltage Networks (PVRLVN), for single phase, two phases and three phases networks. This one is an effective equipment to regulate voltage in customer since the time established by the regulatory standards is a factor that limits the planning and the execution of corrective actions. The first PVRLVN (for two phases network) was developed inside a Research & Development Project financed by AES Eletropaulo, a Brazilian energy distribution company. Then, the PVRLVN for single phase and three phases were developed, designed and tested in a laboratory and in a real grid. Those were installed in several different locations in actual network of the AES Eletropaulo and AES Sul, both Brazilian distribution companies. Also, software for simulating alternatives and works to amend voltage levels provided to affected low voltage customers was developed.

Simulation of photovoltaic systems and microgrids in distribution networks

This paper discusses the connection of photovoltaic system, including microgrids formation, in power distribution networks. The proposed model integrates the descriptive elements of a photovoltaic system: solar radiation, typical load behaviors (residential, commercial and industrial). Based on the developed methodology, a computer implementation of the modules for simulation and impact analysis of photovoltaic generation penetration has been carried out. In order to evaluate the methodology case study simulations have been performed.

Thermal Simulation of Underground Power Distribution Transformers

This paper presents the differential equations that model the heat flow of power transformers located in underground vaults. The solution procedure results in the hot spot winding temperature and its time variation through the daily load cycle. A set of simulations is carried out to evaluate the transformers thermal behavior during overload and contingency conditions. In such simulations the loss of life is estimated to objectively evaluate the technical and economical performance of the power transformer. The air flow in the ventilation system is considered, to search the optimal conditions of heat transfer to the external environment. The paper also considers the conditions in which the forced ventilation system can be switched off.

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.