Claiton M. Franchi

Hybrid method for control of voltage regulation applied in micro hydro power station

This paper deals with the development of a hybrid method of control for voltage regulation in micro hydro power station using self-excited induction generation. The proposed method performs the voltage regulation with the use of capacitor banks plus static VAR compensator. A considerable literature review was undertaken to identify the key control systems for voltage regulation applied to self-excited induction generator. A control algorithm and a project for the variable capacitors are proposed based on the resolution of normative procedures of Electricity Distribution in the National Electric System. Simulation and experimental results are presented to demonstrate the performance of the proposed hybrid method for the voltage regulation of the self-excited induction generator during variations of different types of load. Moreover, experimental results concerning the analysis of reactive power processed by the static VAR compensator during its operation in the hybrid method are obtained. These results are compared with the results obtained through the method that uses only the static VAR compensator, where the hybrid method has advantages in terms of reduction of the size of the static VAR compensator.

Development of a variable speed wind turbine emulator for research and training

This paper describes the development of a variable speed wind turbine emulator used for educational purposes. The emulator reproduces different wind conditions and turbine modes of operation. The grid connection system is identical with the one used in a real wind turbine, model DR-14. Therefore, the emulator provides hands on experience to students giving them insight into wind energy conversion systems (WECS) under different operating conditions. A supervisory control and data acquisition (SCADA) system was developed in order to allow wind turbine monitoring and parameters setting with a user-friendly interface. Communication networks were established to transfer data and signals between software and hardware to reproduce the wind turbine behavior.

Supervisory and control system development applied to distributed generation using Web tools

This paper proposes a system of control and data acquisition (SCADA) to be applied in a distributed generation system. This system was developed with low-cost technology and it is based in wireless communication to perform the exchange of information between generation system and SCADA. The implementation of the proposed system contributes to operation, monitoring and maintenance of systems named smart grids, allowing the management of different generation sources, such as hydro, solar, wind, and others, through conventional monitoring systems like mobile devices, employing Web tools. Experimental results are presented in order to demonstrate the applicability of the system developed.

Synchronization method and frequency tracking applied on voltage converters

This paper proposes a new closed-loop synchronization method for single-phase voltage converters. It presents a good performance under highly distorted grid voltages. Moreover, it has a good performance in terms of distortions in the synchronization signals and it has a good transient performance due amplitude, frequency and angle disturbances. In addition, a frequency adaptation algorithm is proposed for applications where large frequency variations are expected, such as in weak grids. This method can be extended for three-phase systems, applied in three-phase PWM converters. Experimental results using a DSP are given to demonstrate the good performance of the proposed synchronization method.

New hybrid topology of voltage regulation applied in three-phase four-wire system based on induction generator

This paper deals with the development of a new hybrid topology for voltage regulation in micro hydro power station using self-excited induction generator applied in three-phase four-wire systems. The proposed topology is a combination of a three-phase four legs static VAR compensator (SVC) and capacitor banks connected in parallel to the AC voltage bar. It is considered a three wires generator with no accessible neutral point being the neutral terminal for the load created through the neutral terminal of the excitation capacitor and the fourth leg of SVC, which provides the choice to connect the loads either star or delta configurations. A control algorithm and a project for the variable capacitors are proposed based on the specifications of the SVC. The proposed generating system is modeled and simulated in MATLAB. Simulation results and preliminary experimental results are presented to demonstrate the performance of the proposed new hybrid method for the voltage regulation of the self-excited induction generator. In the sequence, simulation results are presented in order to demonstrate the capability of the proposed system for feeding three-phase and single-phase balanced and unbalanced loads, with no distortion of the generated voltages.

Small wind turbine communication system implementation

This paper presents the research and development of a communication system that allows the information exchange between the nacelle and the tower base reducing cabling costs and complexity. The proposed infrastructure allows data acquisition and system supervision of distinct wind turbines/generators and its electrical conversion systems according to the IEC 61400-25 standard. The system implementation uses an Ethernet network allowing Digital Signal Controllers and an Embedded PC to share information via a TCP/IP based protocol. The Embedded PC also serves as outstation to supply process data to a WPP Supervisory and Data Acquisition/Energy Management System (SCADA/EMS). The whole implementation was tested in a small wind turbine prototype. Results associated with this prototype are described. The prototype will be used as basis to disseminate standardized technology to local manufacturers.

Development of communication system for wind turbines

In the last decade Brazil had a considerable economic growth, resulting in a significant increase in demand for electric power. Because of that, investments were made to search for new alternatives technologies for the diversification of the Brazilian energy matrix. The generation of electricity from wind, called wind energy, presents itself as one of the most viable alternative energy to provide the increased demand. The communication between the components and devices in a wind power plant is an essential feature for a safe and efficient operation. This includes data acquisition and system supervision. The IEC 61400-25 standard specifies the communications for monitoring and control of wind power plants, like communication protocols, information models and others. The DNP3 (Distributed Network Protocol) protocol (initially used for electric utility, oil & gas, water/waste water and security industries) was selected for the 61400-25 implementation. This paper presents a communication system that exchange information between nacelle and control panel using Digital Signal Controllers and a Embedded PC employing TCP/IP protocol tested in a 20 kW wind turbine prototype.

Implementation of an Indirect Control Structure for Composition in a Hybrid Distillation Column

In this paper a PID controller is proposed to ensure the fuel ethanol composition at desired value, above 92.5°INPM, at the same time as saving energy through the minimal use of reboiler power. Due to the fact that composition analyzers are expensive and have a high response time, an inference model was developed in which the product composition is inferred from the product temperature and thermodynamics equations, enabling the monitoring and the indirect control a posteriori of this variable. In addition, the inference of composition allows defining the reference value of the product temperature, which ensures the fuel ethanol production at the desired composition.

Online real-time inference of ethanol composition in a mixed distillation column

Abstract The main indicator of the distilled ethanol quality is its composition. In general, the online composition analyzers are not available due to their high cost. To overcome the lacking of devices to measure online and at real-time the process composition, we have proposed a soft-sensor to work as a virtual analyzer. Among the techniques available in the literature to achieve this goal, we have chosen the identification and neural networks. Both are used to infer online the ethanol composition through the real-time measured temperatures. According to our results, the neural networks have shown better performance in the composition inference. Further, this technique as soft-sensor was implemented in a SCADA (Supervisory Control And Data Acquisition) software in order to monitor the distilled ethanol composition.