José Roberto Camacho

Synchronous generator, excitation and speed governor modeling in ATP-EMTP for interconnected DG Studies

The main task in this paper is to present a performance analysis of a distribution network in the presence of a synchronous generator with its speed and voltage regulators, in parallel with the distribution system, for distributed generation studies. Must be highlighted that this generator is driven by a steam turbine, and the whole system with regulators and the equivalent of the power authority system in the point of connection (PAC) are modeled in the ldquoATP - Alternative Transients Programrdquo. Technical questions studied here refer to steady-state voltage profile, voltage stability, voltage dip due to a balanced three-phase fault, load rejection, distribution line outage and the behavior of machine regulators facing the aforementioned contingencies. Results show that, in some cases, the independent power producer (IPA) can be a menace to the physical integrity of the system and in other cases can be very beneficial to the distribution system in the point of connection.

Three-phase transformer representation using FEMM, and a methodology for air gap calculation

This work deals with the representation of three-phase and three-limb transformers in two dimensions using FEMM (finite element methods on magnetics). The transformer magnetization curve is obtained using the magnetization characteristic for the silicon steel used when assembling the transformer core, associated to the air gaps inherent to the assembling process. A method for the calculation of the air gaps reluctance is presented and it is based on the transformer magnetic circuit and on the maximum value in each winding for the magnetization current waveform, such current is obtained through the no-load test. The magnetic flux distribution in the values and the effects of inherent air gaps in the magnetization current is analyzed. Through the use of post-processing procedures, the transformer leakage reactance is calculated and compared with values obtained through the experimental method. Therefore, one of the objectives, is to explain a method to insert some of the transformer assembling imperfections in the computer model.

ATP on the impact analysis of an independent power producer in a distribution network

The main task in this paper is to present a performance analysis of a distribution network in the presence of a synchronous generator with its speed and voltage regulators, in parallel with the distribution system, for distributed generation studies. Must be highlighted that this generator is driven by a steam turbine, and the whole system with regulators and the equivalent of the power authority system in the point of connection are modeled in the ldquoATP - Alternative Transients Programrdquo. Technical questions studied here refer to steady-state voltage profile, voltage stability, voltage dip due to a balanced three-phase fault, load rejection, distribution line outage and the behavior of machine regulators facing the aforementioned contingencies. Results show that, in some cases, the independent generation can be a menace to the physical integrity of the system and in other cases can be very beneficial to the distribution system in the point of connection.

Steam Turbines Under Abnormal Frequency Conditions in Distributed Generation Systems

Considerable efforts have been developed to encourage the installation of independent electricity producers in distribution systems. Obvious example of such efforts is demonstrated by the attempt to standardize their interconnection and protection requirements. However, this standardization can be difficult due to variations in the design of distribution circuits, the various types of generators coupled to the network and the particular requirements of each utility. However, a series of questions points to the development of further studies to ensure the quality of electric power, the system transient stabilty and lifetime of the blades of steam turbines (Moura et al.,2011).

The dynamic interaction of independent power producer synchronous machines connected to a distribution network in ATP-EMTP

The main task in this paper is to present a performance analysis of a distribution network in the presence of two synchronous generators in parallel, with its speed and voltage regulators modeled with TACS - Transient Analysis of Control Systems, for distributed generation studies. This type of configuration is common in systems where renewable fuels are used as sugar cane bagasse or straw. Must be highlighted that these generators are driven by steam turbines, and the whole system with regulators and the equivalent of the power authority system in the point of connection (CCP - Common Coupling Point) are modeled in the “ATP-EMTP - Alternative Transients Program”. Technical questions studied here refer to steady-state voltage profile, voltage stability, voltage dip due to a balanced three-phase fault, load rejection, distribution line outage and the behavior of machine regulators facing the aforementioned contingencies. Results show that, in some cases, the independent power producer (IPP) can be a risk to the physical integrity of the system and in other cases can be very beneficial to the distribution system in the point of connection.

A Contribution to the Study of the Estimate Hydroelectric Potential for Small Hydropower Plant

The aim of this work is to study and develop a methodology for the first stage of deployment of a Small Hydropower Plant (SHP), the Estimate Hydroelectric Potential, stage in which is studied the favorable and unfavorable situations to the deployment of small plants. Basing on environmental and technical criteria of a watershed, according secondary data provided by agencies and institutions responsible for each criterion. Data collections for the study observe the geological and geotechnical, environmental, infrastructure and logistics, water availability and topography aspects. Moreover, it presents the use of GIS (Geographic Information Systems) and it uses the Hydrology Statistics for the hydrological study, to verify the flow of a river or precipitation at a local or region. At the end, it presents the estimate average energy generated, or average power, basing first on the variation of flow over an average year, and constant height. It was applied a study case of the methodology in the watershed of the Tijuco river, limited to the city of Ituiutaba ‑ MG. It was found that the adopted tool is easy to use, reliable and could be adopted for the studies and the calculation of the estimated average energy generated from the statistical analysis of the flow rate for the Tijuco River provided an attractive potential hydroelectric.

Linear temperature model for fuel cell simulators

Alternative sources of energy has been the subject of study by researchers, is the need to master the technology or by the growing demand for renewable energy sources. Many studies have turned to survey models for simulation of fuel cells as an aid in the manufacture of electronic circuits for integration and use of energy generated by this kind of power source, due to the high cost of these equipments and used fuel (hydrogen). This work hereby presents a simulation model that includes the effect of the variation of temperature with the requested cell current. Such a model has been developed from tests on a fuel cell of 1,2kW - Nexa Power Module, using the identification by the method of least squares with pseudo-random binary signals and optimization tools.

Design of Three-Phase Induction Machine Using Differential Evolution Algorithm

In the present day, design of engineering systems appears as a line of research of great interest due the many applications that can be found in different areas of science and engineering. In this setting, design of induction motor, whose functions base are induce alternating currents in the rotor circuit, by the magnetic field rotating produced the stator coils, appears as an interesting theme research already which is directly related to manufacturing costs motors. In this context, this work aims the design of a three-phase induction motor using the Differential Evolution Algorithm. For this purpose considered minimizing loss and cost on motor by determining the geometric variables vector characterizing the model mathematical presented. To solve these problems is used the MODE algorithm (Multiobjective Optimization Differential Evolution) and the outcome is compared to the NSGA II algorithm (Non-dominated Sorting Genetic Algorithm II).

Prospects of Small Hydropower Technology

Small hydropower (SHP) belongs to renewable energy technology group and is a form of attractive power generation environmental perspective because of its potential to be found in small rivers and streams. Many countries use the technology of small hydro as a renewable energy source in order to minimize existing environmental effects in the production of electricity and have the maximum use of water, a renewable resource. This technology has shown prominence on the world stage with seemingly insignificant environmental effects on rivers, water channels, and dams.

Design and Finite Element Analysis for the Single-Phase Variable Reluctance Motor

The article presents a review of the design procedures for a switched reluctance machine. A finite element simulation is used to obtain the operating data of the designed prototype. These data are flux linkage, inductance, torque and magnetic saturation. With them it is possible to profile and inductance torque and verification of design for the prototype. It also presents a criterion for analysis operational limit for the machine, based on data collected in the simulation.