777 research outputs found

    Development and implementation of a LabVIEW based SCADA system for a meshed multi-terminal VSC-HVDC grid scaled platform

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    This project is oriented to the development of a Supervisory, Control and Data Acquisition (SCADA) software to control and supervise electrical variables from a scaled platform that represents a meshed HVDC grid employing National Instruments hardware and LabVIEW logic environment. The objective is to obtain real time visualization of DC and AC electrical variables and a lossless data stream acquisition. The acquisition system hardware elements have been configured, tested and installed on the grid platform. The system is composed of three chassis, each inside of a VSC terminal cabinet, with integrated Field-Programmable Gate Arrays (FPGAs), one of them connected via PCI bus to a local processor and the rest too via Ethernet through a switch. Analogical acquisition modules were A/D conversion takes place are inserted into the chassis. A personal computer is used as host, screen terminal and storing space. There are two main access modes to the FPGAs through the real time system. It has been implemented a Scan mode VI to monitor all the grid DC signals and a faster FPGA access mode VI to monitor one converter AC and DC values. The FPGA application consists of two tasks running at different rates and a FIFO has been implemented to communicate between them without data loss. Multiple structures have been tested on the grid platform and evaluated, ensuring the compliance of previously established specifications, such as sampling and scanning rate, screen refreshment or possible data loss. Additionally a turbine emulator was implemented and tested in Labview for further testing

    Control and operation of a Vertical Axis Wind Turbine

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    Research in wind power generation technology is a topic of high relevance in the context of renewable energy systems. This project aims to develop and implement an automatic operation and control system for an experimental vertical axis wind turbine (VAWT) located at Lunds Tekniska Högskola, in Sweden. Supervisory control and data acquisition systems (SCADA) are increasingly considered indispensable in industrial scale wind power plants with the purpose of optimizing power production and monitoring the operation conditions in realtime to improve safety and reduce downtime and costs. Variable speed control is widely used for maximizing power extraction. In this project, a Maximum Power Point Tracking (MPPT) algorithm was successfully implemented in order to optimize power production. Hill Climb Search (HCS) was the chosen control method, since there is no knowledge about the optimum tip speed ratio of the rotor or the wind turbine maximum power curve. A state-machine model was developed to manage the operation of the wind turbine. The control sequence is implemented in programmable logic controllers from National Instruments, and data from the power converters and wind speed measurement is acquired and analyzed in the system. Performance tests were ran to investigate the optimum CP and the wind speed at which the wind turbine is capable of producing power

    Design and Implementation of a True Decentralized Autonomous Control Architecture for Microgrids

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    Microgrids can serve as an integral part of the future power distribution systems. Most microgrids are currently managed by centralized controllers. There are two major concerns associated with the centralized controllers. One is that the single controller can become performance and reliability bottleneck for the entire system and its failure can bring the entire system down. The second concern is the communication delays that can degrade the system performance. As a solution, a true decentralized control architecture for microgrids is developed and presented. Distributing the control functions to local agents decreases the possibility of network congestion, and leads to the mitigation of long distance transmission of critical commands. Decentralization will also enhance the reliability of the system since the single point of failure is eliminated. In the proposed architecture, primary and secondary microgrid controls layers are combined into one physical layer. Tertiary control is performed by the controller located at the grid point of connection. Each decentralized controller is responsible of multicasting its status and local measurements, creating a general awareness of the microgrid status among all decentralized controllers. The proof-of concept implementation provides a practical evidence of the successful mitigation of the drawback of control command transmission over the network. A Failure Management Unit comprises failure detection mechanisms and a recovery algorithm is proposed and applied to a microgrid case study. Coordination between controllers during the recovery period requires low-bandwidth communications, which has no significant overhead on the communication infrastructure. The proof-of-concept of the true decentralization of microgrid control architecture is implemented using Hardware-in-the-Loop platform. The test results show a robust detection and recovery outcome during a system failure. System test results show the robustness of the proposed architecture for microgrid energy management and control scenarios

    Control of distributed renewable energy generation systems in converter-dominated microgrid applications

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    Mención Internacional en el título de doctorThere is a growing interest in the use of renewable Distributed Energy Resources (DERs) that increase the efficiency of the transmission system and reduce the ecological impact of renewable energy infrastructures. At the same time, they reduce the associated capital requirements, thus increasing the potential installation of renewable energy. Microgrids have been proposed as a solution to improve the integration of renewable DERs. By the use of advanced control techniques, they provide a reliable frame for DERs to support the power system operation. As such, Microgrids can be a promising solution to increase renewable energy penetration. However, since renewable DERs are usually interfaced by Power Electronic Converters (PECs), they do not provide the common stabilization characteristics of traditional generation interfaced by Synchronous Generators (SGs). Therefore, there are concerns about the stability of converter-dominated Microgrids. This Thesis focus on the specific requirements of PEC-interfaced renewable DERs operating in Microgrids. An overview of available solutions show that, for PECs to support the Microgrid operation in both grid-connected and islanded modes, they require a synchronizing mechanism that does not rely on the measurement of an external frequency. A promising alternative is to emulate the behavior of traditional SGs in the PEC control system with the so-called Virtual Synchronous Machine (VSM) solutions. The synchronization system underlying to these proposals is analyzed. A comparison with the use of traditional frequency measurement systems, namely Phase-Locked Loops (PLLs), in the support of the Microgrid power balance is addressed, showing that the PEC synchronization system has a direct effect on the Microgrid stability. The Thesis includes a new proposal to ensure synchronous operation based on the use reactive power, instead of active power as in VSMs, that does not require frequency measurements. A dynamic model of a grid-connected PEC is used to demonstrate that reactive power can be used to ensure synchronism. This Reactive Power Synchronization system is used to propose a solution for the black-start of Wind Energy Conversion Systems (WECSs), so that they can contribute to the restoration of the power system following a blackout. The proposed control systems are validated with experimental results of a grid connected PEC and an isolated WECS.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Luis Rouco Rodríguez.- Secretario: Emilio José Bueno Peña.- Vocal: Roberto Alves Baraciart

    A flexible experimental laboratory for distributed generation networks based on power inverters

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    In the recently deregulated electricity market, distributed generation based on renewable sources is becoming more and more relevant. In this area, two main distributed scenarios are focusing the attention of recent research: grid-connected mode, where the generation sources are connected to a grid mainly supplied by big power plants, and islanded mode, where the distributed sources, energy storage devices, and loads compose an autonomous entity that in its general form can be named a microgrid. To conduct a successful research in these two scenarios, it is essential to have a flexible experimental setup. This work deals with the description of a real laboratory setup composed of four nodes that can emulate both scenarios of a distributed generation network. A comprehensive description of the hardware and software setup will be done, focusing especially in the dual-core DSP used for control purposes, which is next to the industry standards and able to emulate real complexities. A complete experimental section will show the main features of the system.Peer ReviewedPostprint (published version

    An Adaptive Protection for Radial AC Microgrid Using IEC 61850 Communication Standard : Algorithm Proposal Using Offline Simulations

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    The IEC 61850 communication standard is getting popular for application in electric power substation automation. This paper focuses on the potential application of the IEC 61850 generic object-oriented substation event (GOOSE) protocol in the AC microgrid for adaptive protection. The focus of the paper is to utilize the existing low-voltage ride through characteristic of distributed generators (DGs) with a reactive power supply during faults and communication between intelligent electronic devices (IEDs) at different locations for adaptive overcurrent protection. The adaptive overcurrent IEDs detect the faults with two different preplanned settings groups: lower settings for the islanded mode and higher settings for the grid-connected mode considering limited fault contributions from the converter-based DGs. Setting groups are changed to lower values quickly using the circuit breaker status signal (XCBR) after loss-of-mains, loss-of-DG or islanding is detected. The methods of fault detection and isolation for two different kinds of communication-based IEDs (adaptive/nonadaptive) are explained for three-phase faults at two different locations. The communication-based IEDs take decisions in a decentralized manner, using information about the circuit breaker status, fault detection and current magnitude comparison signals obtained from other IEDs. However, the developed algorithm can also be implemented with the centralized system. An adaptive overcurrent protection algorithm was evaluated with PSCAD (Power Systems Computer Aided Design) simulations, and results were found to be effective for the considered fault cases.© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

    Validation Platform for Grid Forming Control Strategies of Power Electronic Inverters. From Component to System Level Validation

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    Development of two platforms used to perform component and system level validation of grid forming techniques. In this thesis novel grid forming techniques are implemented in a control card and tested in real-time

    SCR-Based Wind Energy Conversion Circuitry and Controls for DC Distributed Wind Farms

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    The current state of art for electrical power generated by wind generators are in alternating current (AC). Wind farms distribute this power as 3-phase AC. There are inherent stability issues with AC power distribution. The grid power transfer capacity is limited by the distance and characteristic impedance of the lines. Furthermore, wind generators have to implement complicated, costly, and inefficient back-to-back converters to generate AC. AC distribution does not offer an easy integration of energy storage. To mitigate drawbacks with AC generation and distribution, direct current (DC) generation and high voltage direct current (HVDC) distribution for the wind farms is proposed. DC power distribution is inherently stable. The generators convert AC power to DC without the use of a back-to-back converter. DC grid offers an easy integration of energy storage. The proposed configuration for the generator is connected to a HVDC bus using a 12 pulse thyristor network, which can apply Maximum Power Point Tracking (MPPT). To properly control the system, several estimators are designed and applied. This includes a firing angle, generator output voltage, and DC current estimators to reduce noise effects. A DSP-based controller is designed and implemented to control the system and provide gate pulses. Performance of the proposed system under faults and drive train torque pulsation are analyzed as well. Additionally, converter paralleling when turbines operate at different electrical power levels are also studied. The proposed new Wind Energy Conversion System (WECS) is described in detail and verified using MATLAB®/ Simulink® simulation and experimental test setup. The proposed solution offers higher reliability, lower conversion power loss, and lower cost. The following is proposed as future work: 1) Study different control methods for controlling the SCR\u27s. 2) Investigate reducing torque pulsations of the PMSG and using the proposed power conversion method for DFIG turbines. 3) Explore options for communication/control between PMSG, circuit protection and grid-tied inverters. 4) Investigate the best possible configuration for DC storage/connection to the HVDC/MVDC bus. 5) Study the filtering needed to improve the DC bus voltage at the generator

    Supervisory control interface for experimental hybrid wind and solar energy system

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    ix, 73 leaves : illustrations (chiefly colour) ; 29 cmIncludes abstract and appendix.Includes bibliographical references (leaves 66-73).A supervisory control interface developed for wind and solar energy system and its control systems are presented in this thesis. The proposed system consists of a wind turbine, a solar panel and a load bank. A power electronics interface, based on various converters, is used to integrate the renewable energy sources. The main goal of the control interface is to maintain the balance between load demand and power supply. The objective of the proposed power management system is to ensure a proper control and coordination between all the sources and loads of the system. The developed power management system algorithm uses a basic cost function to control the power flow from both the energy sources. The supervisory control interface also gives the user an option to control the load priority from the front panel and provides user feedback in case of low power situations. An experimental setup is designed using the National Instruments equipment and LabVIEW software to test the developed control interface. Experimental results for various conditions are presented to validate the power management system algorithms developed in this work
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