Eduardo Verri Liberado

Three-phase four-wire circuits interpretation by means of different power theories

In order to contribute to the discussion of defining a generalized power theory, valid for unbalanced and non linear circuits, this paper discusses the relationship and discrepancies among four modern power theories. Three-phase four-wire circuits, under different conditions, have been analyzed, since the most conflicting and intriguing interpretations take place in case of return conductor occurrence. Simulation results of different load, power supply and line conditions will be discussed in order to elucidate the authors conclusions and to provoke the readers for additional discussions.

Power Quality, Smart Meters and Additional Information from Different Power Terms

This paper shows how the detailed examination of active and nonactive power components may produce new information for modern smart meters. For this purpose, a prototype of electronic power meter has been implemented and applied to the evaluation of the Conservative Power Theory (CPT). Considering five sorts of loads, under four different operating conditions, the experimental results indicate that the CPT is able to provide a good methodology for load characterization, which could possibly benefits consumers and power utilities in several different ways. The results also show that depending on the situation, the analysis of nonactive power terms may be more important than the observation of traditional power quality indices, such as total harmonic distortion, unbalance factors or the fundamental positive sequence power factor.

Selective compensation of reactive, unbalance, and distortion power in smart grids by synergistic control of distributed switching power interfaces

Smart grids feature distributed energy resources interfaced to the grid by means of switching power converters. Synergistic control of these units can considerably increase the distribution efficiency and power quality by limiting the unbalance, reactive, and harmonic currents flowing through distribution lines. This can be achieved by a distributed control and communication architecture which implements suitable control strategies. This paper deals with a control approach, based on conservative power commands, which allows selective elimination of the main causes affecting the power quality, i.e., load asymmetry, harmonics, and useless reactive power flow. As a result, distribution efficiency improves, voltage asymmetry and distortion diminishes, and the distribution infrastructure is better exploited, thus allowing an increase of the hosting capacity of the grid.

Novel expert system for defining power quality compensators

Original expert system for compensation systems definition.Co-relation of recognized power quality indices through a fuzzy rule-based system.Application of the expert system in a 5-node grid with various load configurations.Simulation of the compensators suggested in every application case.Comparison of a result suggested by the expert system and a commonly-used solution. In order to ensure good power quality for modern power systems and/or industrial installations, power conditioning devices have been extensively applied. However, the data analysis for the installation of a determined compensator mainly considers a particular power quality index or disturbance and it is usually based on human expertise. Therefore, this paper proposes a novel expert system that automatically suggests the most appropriate and cost-effective solution for compensating reactive, harmonic and unbalanced current through a careful analysis of several power quality indices and some grid characteristics. Such an expert system is an important tool in real-world applications, where there is a complex scenario in choosing, designing and applying power quality compensators in modern power grids. Since there are no strict boundaries for voltage and current non idealities at distribution level or clear correlation between them and possible solutions, a fuzzy decision-maker was developed to deal with such uncertainties and to embed human expertise in the system. The approach is based on analyzing data from a given time window and providing off-line recommendations for the design and installation of proper compensators. Therefore, the application of the proposed expert system may result in enhanced and faster projects when compared to the traditional design methods for power conditioning. A computational study consisting on applying the suggested compensators for a 5-node network and different load configurations shows the effectiveness of the proposed expert system.

Design of static VAr compensator using a general reactive energy definition

This paper describes a methodology to design Static VAr Compensators (SVC) using the reactive energy definition from Conservative Power Theory. Application of this methodology is presented through simulations of local and distributed compensation approaches. Results show effective compensation of reactive current and load unbalance. Harmonic distortion caused by thyristor controlled reactor has been suitable attenuated by passive filters designed in combination with the SVC.

TOWARDS INTELLIGENT MANUFACTURING

Abstract Abstract This article describes the application of an Artificial Intelligence Planner in a robotized assembly cell that can be integrated to a Flexible Manufacturing System. The objective is to allow different products to be automatically assembled in a single production line with no pre-established assembly plans. The planner function is to generate action plans to the robot, in real time, from two input information: the initial state (disposition of parts of the product in line) and the final state (configuration of the assembled product).

Industrial robotics applied to education

This work describes a ludic proposal for programming learning of industrial robots to be developed by groups of engineering students. Two projects are presented: Tic-tac-toe Opponent Robot and Environmentalist Robot. The first project use competitive search techniques of the Artificial Intelligence, computational vision, electronic and pneumatic concepts for ability decision making for a robotic agent on the tic-tae-toe game. The second project consists of a game that contains a questions and answers database about environmental themes. An algorithm selects the group of questions to be answered by the player, analyses the answers and sends the result to a industrial robot through serial port. According with the player performance, the robot makes congratulation movements and giving a gift to the winner player. Otherwise, the robot makes movements, disapproving the player performance.

Harmonic analysis of static var compensator operating under distorted voltages

The static var compensators (SVC) are still in use in both transmission and distribution grids, due to their reduced costs and high reliability. Especially in distribution grids, on which the voltage harmonic distortion limits are less restrictive, it may cause a considerable harmonic distortion impact when operating under non sinusoidal voltage conditions. Therefore, this paper describes a harmonic analysis methodology for the SVC, considering non-ideal source voltages, in order to determine harmonic power terms that may be used to design and also control harmonic power filters. Application examples are presented and the operation of an experimental SVC prototype is also analysed.

Making use of virtual instrumentation for the evaluation of Std-1459 and FBD method in three-phase four-wire circuits

This paper discusses the design of a virtual instrument for the analysis of three-phase four-wire circuits. Although the flexibility of the proposed instrument in terms of using different methodologies, this paper focuses on the evaluation of several power terms defined in STD 1459 and FDB (Fryze-Buchholz-Depenbrock) approaches. Laboratory measurements are presented and discussed in order to evaluate the developed instrument and the considered power theories.

Simulation of a distributed generator with wireless communication using TrueTime and PLECS

The increasing demand for the use of electricity results in a necessary expansion of the energy matrix through alternative sources, including the participation of small power generators in low or medium voltage. In this scenario, one of the challenges is the automation of network communication process between different devices, such as generator controllers, smart meters etc., in order to facilitate the exchange of information and improve network performance. Therefore, this paper presents a simulation of a distributed generator remotely controlled via wireless communication. The electrical system was implemented using PLECS blockset, while the wireless network was designed using the TrueTime toolbox. In this application, the active power generation is controlled remotely by a wireless communication network and the simulation of a DG remotely controlled trough a ZigBee wireless network is presented. The results of some important variables show that the use of TrueTime toolbox enabled the modeling of wireless network in the same environment on which the control of the DG and network were modeled.