Current differential line protection using a pattern recognition method

This paper presents a new approach to a numerical current differential protection for the transmission lines. The current differential algorithm uses a pattern recognition method. First the acquired current signals are transformed into “dqo” components by applying the Park transformation. The transformed currents will originate typical patterns according the fault type. Using a pattern recognition algorithm the different faulty conditions are identified. Several tests under different fault conditions were performed. The obtained results allow verifying the effectiveness of the proposed approach

Study of the HVDC dual transmission system under faults in the power converters

Trabalho apresentado no Speedam 2016, 22-24 de junho de 2016, Capri, ItáliaHVDC transmission systems based on voltage source converters have lately emerged as a good alternative to conventional AC transmission. In these transmission systems multilevel converters have become a promising energy conversion technology. The reliability of the power converters are extremely important since a fault in these equipments may lead to an unavailability for a long period of the transmission system. Thus, this paper will focuses in HVDC dual transmission system under semiconductor failure conditions. As presented in this paper this structure presents interesting characteristics under the point of view the reliability considering a power semiconductor failure. It will present the consequences for the transmission system when there is a semiconductor fault. A study for the change of the modulation system in order to ensure DC link capacitors voltage balance under a fault condition is also presented. Simulation studies are shown in order to confirm the characteristics of the proposed methodology in normal and fault condition mode.N/

A current differential line protection using a synchronous reference frame approach

This paper presents a new approach for a current differential protection of the transmission lines. This approach is based on the Park transformation or ABC-dqo transformation. Using the ABC-dqo transformation the three phase quantities are transformed into a synchronous rotating reference frame. In this way, the line currents of the three phase system are measured and transformed into three dc components. So, immunity to problems such as sampling misalignment and time delay of the communication channel will be improved. Several test results are presented in order to show the effectiveness of the proposed approach

Distributed energy resources network connection considering reliability optimization using a NSGAII algorithm.

Trabalho apresentado conferência IEEE CPE-POWERENG, 4 a 6 de abril de 2017, Cádiz, EspanhaDistributed Energy Resources (DER) has been widely introduced in distribution networks in response to the increase of environmental awareness of the consumers. The benefits with the use of DER are increased with network reconfiguration, but in some countries exists the impossibility of island operation as well as the obligation to buy all the electricity generated. These limitations, in a network fault situation, causes a waste of resources, because of the unavailability of the DER. On other hand, the location of DER connection under the context of the improvement of the reliability indexes has not been studied. Thus, this paper will propose a multi objective optimization of the location of DER connection considering the switching devices placement to increase network reliability and availability of DER, minimizing at the same time the investment in equipment in a no island operation environment. For the resolution of the proposed formulation, it will be used the multi objective algorithm NSGA-II (Fast Non-dominated Sorting Genetic Algorithm). The formulation of the problem also considers a composite index made up of DER and interruption duration. This approach is applied to a real utility distribution network, with the results presented and discussed.N/

Road Motion Control Electric Vehicle with Speed and Torque Observer

This paper presents an electric vehicle (EV) with two independent rear wheel drives and with an electric differential system. A model of the vehicle dynamic model is presented. The electric differential was implemented assuring that, in straight right trajectory, the two wheels drives roll exactly at same velocity and, in curve, the difference between the two velocities assure a vehicle trajectory. A speed and torque observer for DC motor was also proposed and simulated. Analysis and simulation results of the proposed system are presented.Com o apoio RAADRI

Transmission lines protection based on the current eigenvalues differential concept

This work presents a new approach for a current differential protection of the transmission lines. The proposed approach is based on the Clarke-Concordia transformation and principal component analysis. First the acquired current signals are transformed into “αβo” components by applying the Clarke-Concordia transformation. This allows obtaining typical patterns. To identify these patterns a principal component analysis is performed. Several tests under different fault conditions were performed. The obtained results allow verifying the effectiveness of the proposed approach

A power amplifier system for testing of distance relay operating characteristic

This paper describes a power amplifier system for testing of distance relay operating characteristic. This power amplifier is based on two three phase inverters with a neutral wire. The output power currents and voltages are controlled by a sliding mode controller. A developed matlab/simulink digital simulator generates the test signals. This test signals are converted in current and voltage references using a microcontroller to connect the digital simulator to the power converter amplifier. Experimental results from a laboratory prototype are presented and discussed

Wireless Power Transfer Impact on Data Channel

Trabalho apresentado no 23rd International Symposium on Power Electronics, Electrical Drives, Automation and Motion (Speedam, 2016), 22-24 junho de 2016, Capri, ItáliaThis paper presents measurement results and analysis of the interference produced by the high-power electromagnetic field in a wireless energy transfer system. Through this analysis it is expected to be possible to evaluate the influence of the strong electromagnetic field on the data transmission channel. The wireless power transfer aimed at electric vehicles battery charging receives a great deal of attention in the recent years. However, the performance of those systems depends on the exchange of information between the transmitter and the receiver, e.g. vehicle identification, frequency, required power, payment information. Thus, it is essential to ensure that the electromagnetic interference, generated by the wireless power transfer system will not influence or disrupt the communication between the transmitter and the receiver.N/

A Buck-Boost Converter with Extended Duty-Cycle Range in the Buck Voltage Region for Renewable Energy Sources

Publisher Copyright: © 2023 by the authors.Buck-boost DC–DC converters are useful as DC grid interfaces for renewable energy resources. In the classical buck-boost converter, output voltages smaller than the input voltage (the buck region) are observed for duty cycles between 0 and 0.5. Several recent buck-boost converters have been designed to present higher voltage gains. Nevertheless, those topologies show a reduced duty-cycle range, leading to output voltages in the buck region, and thus require the use of very low duty cycles to achieve the lower range of buck output voltages. In this work, we propose a new buck-boost DC-DC converter that privileges the buck region through the extension of the duty-cycle range, enabling buck operation. In fact, the converter proposed here allows output voltages below the input voltage even with duty cycles higher than 0.6. We present the analysis, design, and testing of the extended buck-boost DC-DC converter. Several tests were conducted to illustrate the characteristics of the extended buck-boost DC-DC converter. Test results were obtained using both simulation software and a laboratory prototype.publishersversionpublishe

Implementation of a low cost data acquisition board for photovoltaic arrays analysis and diagnostic

Testing PV modules are one of the important procedures to ensure the conformity with the standards and quality of this equipment’s. To implement some of the PV modules tests a data acquisition system is required. This paper presents the design and implementation of a data acquisition system for photovoltaic systems. The developed system is characterized by a low cost board based on a microcontroller. The description of the hardware as well an application to test its performance is presented. The developed system can be used for reading, storing and analyzing information from several photovoltaic systems. Experimental tests are presented to confirm the characteristics of the developed data acquisition board.Com o apoio RAADRI