Download or read book Control and Protection of VSC based Multi terminal DC Networks written by Epameinondas Kontos and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing global energy needs and the high integration of renewable energy generation require long-distance power transmission and multi-terminal complex grids. High-voltage direct current (HVDC) is an appealing alternative for future grids. Recent HVDC research has focused on voltage-source converter (VSC) technology. However, VSC is unable to handle DC contingencies. Thus far, AC breakers have been the only way to clear DC faults, though with significant economic and societal consequences. Other protection concepts include multi-level converters and faulty line identification methods. Still, DC breakers are necessary to isolate the faulty line from the network. The goal of this work is to investigate multi-terminal grid topologies under fault cases and analyze the impact of current limiting measures and control strategies on the developing DC fault currents. DC breaker technologies are studied and compared based on the total fault interruption time and the system post-fault operation restoration. With the analyzed concepts, HVDC system designers will be able to understand and tackle DC faults to facilitate an uninterruptible power flow amongst several different AC grids.

Download or read book Dynamic Modeling and Control of Vsc Based Multi Terminal Dc Networks written by Sílvio Rodrigues and published by LAP Lambert Academic Publishing. This book was released on 2012-07 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the next years, several offshore wind farms will be installed all over Europe. Due to the technologic advantages that voltage-source converters have when compared to other available options, there is a strong possibility that this will be the technology chosen to connect offshore wind farms. Such assumption intensifies the need of studying and simulating the control methods for these systems. Therefore, the purpose of this work is to present and explain all the models that are needed to simulate, with the necessary detail, the electric systems of the offshore wind farms, the high-voltage converters and the DC grid. The control method of the DC system is given and several methods to control the DC grid voltage are presented and compared. This way, it will be possible for several countries connected to the multi-terminal DC grid not only to receive energy from the offshore wind farms, according to desired criteria, but also to trade energy with other nations.

Download or read book Protection Principle and Technology of the VSC Based DC Grid written by Bin Li and published by Springer Nature. This book was released on 2020-08-13 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses key techniques of protection and fault ride-through in VSC-HVDC grids, including high-speed selective protection, DC fault current limitation, converter restarting, and DCCB reclosing strategies. It investigates how high-speed transient-variable-based protection can be used to improve grids’ acting sensitivity, acting reliability, and ability to withstand high transition resistance compared with traditional protection. In addition, it discusses the applicability of the pilot protections, including the current differential protection and travelign-wave based protection, in the dc grid, as well as the improved methods. Furthermore, it proposes several DC FCL topologies, which are suitable for DC grids. Lastly, in the context of overhead line application conditions, it explores converter restarting and DCCB reclosing strategies, which not only identify the fault property, but also limit the secondary damage to the system, improving the system’s operation security and reliability. As such, the book offers a comprehensive overview of original and advanced methods and techniques for the protection of VSC-HVDC grids.

Download or read book Control and Operation of Multi terminal VSC DC Networks written by Cătălin Gavriluţă and published by . This book was released on 2015 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the past century, ac networks have been established as the standard technology for electrical power transmission system s. However, the de technology has not disappeared completely from this picture. The capability of de systems to transmit higher power over longer distances, the possibility of interconnecting asynchronous networks, and their high efficiency has maintained the interest of both industry and academia. Historically, systems based on dc-generators and mercury valves were used for de power transmission applications, but, by the 90's, all installations were thyrsi tor-based line commutated converters (LCC). In 1999, the first system based on voltage source converters (VSC) was installed in Gotland, Sweden, marking the beginning of a new era for de transmission. Over the past 15 years, the power rating of VSC-based de transmission systems has increased from 50 to 700 MVV, the operating voltage from 120 to 500 kV, meanwhile , the covered distances have become as long as 950 km (ABB's HVDC-light installation in Namibia in 2010). The work presented in this thesis is oriented towards the control and operation of multi-terminal VSC de (MTDC) networks. The proposed approach is a hierarchical control architecture, inspired by the well-established automatic generation control strategy applied to ac networks. In the proposed architecture, the primary control of the MTDC system is decentralized and implemented using a generalized droop strategy More than analyzing the behavior of the primary control, this thesis provides a methodology for designing the various parameters that influence this behavior. The importance of correctly dimensioning the VSC's output capacitor is underlined as this element, when set in the context of a MTDC network, becomes the inertial element of the grid and it has a direct impact on the voltage overs hoots that appear during transients. Further on, an improved droop control strategy that attenuates the voltage oscillations during transients is proposed. Also part of the proposed hierarchical control, the secondary control is centralized and it regulates the operating point of the network so that optimal power flow (OPF) is achieved . Compared to other works, this thesis elaborates, both analytically and through simulations, on the coordination between the primary and secondary control layers.

Download or read book Multi terminal Direct Current Grids written by Nilanjan Chaudhuri and published by John Wiley & Sons. This book was released on 2014-09-09 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: A generic DC grid model that is compatible with the standard AC system stability model is presented and used to analyse the interaction between the DC grid and the host AC systems. A multi-terminal DC (MTDC) grid interconnecting multiple AC systems and offshore energy sources (e.g. wind farms) across the nations and continents would allow effective sharing of intermittent renewable resources and open market operation for secure and cost-effective supply of electricity. However, such DC grids are unprecedented with no operational experience. Despite lots of discussions and specific visions for setting up such MTDC grids particularly in Europe, none has yet been realized in practice due to two major technical barriers: Lack of proper understanding about the interaction between a MTDC grid and the surrounding AC systems. Commercial unavailability of efficient DC side fault current interruption technology for conventional voltage sourced converter systems This book addresses the first issue in details by presenting a comprehensive modeling, analysis and control design framework. Possible methodologies for autonomous power sharing and exchange of frequency support across a MTDC grid and their impact on overall stability is covered. An overview of the state-of-the-art, challenges and on-going research and development initiatives for DC side fault current interruption is also presented.

Download or read book HVDC Grids written by Dirk Van Hertem and published by John Wiley & Sons. This book was released on 2016-02-23 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses HVDC grids based on multi-terminal voltage-source converters (VSC), which is suitable for the connection of offshore wind farms and a possible solution for a continent wide overlay grid. HVDC Grids: For Offshore and Supergrid of the Future begins by introducing and analyzing the motivations and energy policy drives for developing offshore grids and the European Supergrid. HVDC transmission technology and offshore equipment are described in the second part of the book. The third part of the book discusses how HVDC grids can be developed and integrated in the existing power system. The fourth part of the book focuses on HVDC grid integration, in studies, for different time domains of electric power systems. The book concludes by discussing developments of advanced control methods and control devices for enabling DC grids. Presents the technology of the future offshore and HVDC grid Explains how offshore and HVDC grids can be integrated in the existing power system Provides the required models to analyse the different time domains of power system studies: from steady-state to electromagnetic transients This book is intended for power system engineers and academics with an interest in HVDC or power systems, and policy makers. The book also provides a solid background for researchers working with VSC-HVDC technologies, power electronic devices, offshore wind farm integration, and DC grid protection.

Download or read book Control and Protection of Multi terminal DC Transmission Systems Based on Voltage source Converters written by Lianxiang Tang and published by . This book was released on 2003 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Digital simulations have been used to demonstrate the feasibility of the control and protection strategies." --

Download or read book Planning and Control of Expandable Multi Terminal VSC HVDC Transmission Systems written by Roni Irnawan and published by Springer Nature. This book was released on 2019-09-03 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses novel methods for planning and coordinating converters when an existing point-to-point (PtP) HVDC link is expanded into a multi-terminal HVDC (MTDC) system. It demonstrates that expanding an existing PtP HVDC link is the best way to build an MTDC system, and is especially a better option than the build-from-scratch approach in cases where several voltage-sourced converter (VSC) HVDC links are already in operation. The book reports in detail on the approaches used to estimate the new steady-state operation limits of the expanded system and examines the factors influencing them, revealing new operation limits in the process. Further, the book explains how to coordinate the converters to stay within the limits after there has been a disturbance in the system. In closing, it describes the current DC grid control concept, including how to implement it in an MTDC system, and introduces a new DC grid control layer, the primary control interface (IFC).

Download or read book Cooperative Power Sharing Control in Multi terminal Voltage Source Converter high Voltage Direct Current written by Hasan Alrajhi Alsiraji and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Multi-terminal high voltage DC (MTDC) system is a viable solution for increasing an electrical power generation to interconnect renewable resources into an AC grid. Using a voltage source converter (VSC) allows independent control of a reactive and an active power flow. Based on the literature, there is a trend to implement MTDC into a distribution grid system in the future. Power sharing control among MTDCs is an important and critical consideration from the point of view of stability and operation. MTDC systems consist of multi-input converters (rectifiers) and single or multi-output converters (inverters), thus controlling and operating MTDC systems pose many challenges due to their complexity. Since the DC link in MTDC systems might have several connection nodes all having a common DC voltage value, using the DC voltage value as a common reference for all terminal control loops makes it possible to get a cooperative control performance. An economical autonomous control to share active power among MTDC systems based on the availability of active power or power management policy is proposed in this thesis. Power sharing among MTDC systems has a priority or sequential procedural problem because of the use of the conventional droop strategy. On the other hand, using predefined or constant power sharing does not provide the available power that can be shared when it is not being consumed by another inverter. The proposed strategy solves these issues using different options. In this thesis, the test system consists of four simulated VSC terminals based on a detailed switching VSC model with two AC voltage levels. The MTDC system is simulated in a PSCAD/EMTDC environment. The simulation results show a significant decrease in operational costs and protection from overloading which had been an issue.

Download or read book Design Control and Application of Modular Multilevel Converters for HVDC Transmission Systems written by Kamran Sharifabadi and published by John Wiley & Sons. This book was released on 2016-08-22 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design, Control and Application of Modular Multilevel Converters for HVDC Transmission Systems is a comprehensive guide to semiconductor technologies applicable for MMC design, component sizing control, modulation, and application of the MMC technology for HVDC transmission. Separated into three distinct parts, the first offers an overview of MMC technology, including information on converter component sizing, Control and Communication, Protection and Fault Management, and Generic Modelling and Simulation. The second covers the applications of MMC in offshore WPP, including planning, technical and economic requirements and optimization options, fault management, dynamic and transient stability. Finally, the third chapter explores the applications of MMC in HVDC transmission and Multi Terminal configurations, including Supergrids. Key features: Unique coverage of the offshore application and optimization of MMC-HVDC schemes for the export of offshore wind energy to the mainland. Comprehensive explanation of MMC application in HVDC and MTDC transmission technology. Detailed description of MMC components, control and modulation, different modeling approaches, converter dynamics under steady-state and fault contingencies including application and housing of MMC in HVDC schemes for onshore and offshore. Analysis of DC fault detection and protection technologies, system studies required for the integration of HVDC terminals to offshore wind power plants, and commissioning procedures for onshore and offshore HVDC terminals. A set of self-explanatory simulation models for HVDC test cases is available to download from the companion website. This book provides essential reading for graduate students and researchers, as well as field engineers and professionals who require an in-depth understanding of MMC technology.

Download or read book Modeling of Multi terminal VSC based HVDC Systems written by Mohammed Mabrook Alharbi and published by . This book was released on 2014 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Improving the efficiency and operation of power transmission is important due to the continual increase in demand for electric power. In addition, many remote areas throughout the world lack sufficient access to electricity. Unfortunately, utilities cannot satisfy the high demand of power by building new power stations because of economic and environmental reasons. However, utilities can increase generation and transmission line efficiencies by controlling the power flow through their systems. One new attractive technology that enables the control of power flow in the system is Voltage-Source-Converter High Voltage Direct Current (VSC-HVDC) transmission. Multi-terminal-HVDC (M-HVDC) can be built using VSC technology. A model of a three-terminal VSC-HVDC system is presented in this thesis. One of the converters is used to regulate the DC voltage while the others converters control the active power independently and bi-directionally. The vector control strategy and pulse width modulation (PWM) technique are described and implemented in PSCAD/EMTDC. In addition, the region of controllability as a function of power flow has been analyzed. Furthermore, the steady-state and dynamic response characteristics as a function of capacitor size has been investigated"--Abstract, page iii.

Download or read book DC Protection of Multi terminal VSC HVDC Systems written by Bin Chang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book DC Technology in Utility Grids written by Sedigheh Rabiee and published by BoD – Books on Demand. This book was released on 2021-12-17 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: The assembly of this study started in 2013 during the preparation of the foundation of the Flexible Electrical Networks (FEN) Research Campus, an institution supported by the German Federal Ministry of Education and Science, concentrating on DC technology in power grids as an enabler for the energy transition. It reflects the state-of-the-art and research needs of DC technology against the background of application in public grids up until the year 2015. Topics as components, control, management and automation, high-, medium, and low-voltage grid concepts as well as social dimensions, economics, and impact on living beings are considered. After substantial editorial effort, its first public edition has become ready now. The aim of FEN is to investigate and to develop flexible power grids. Such grid will safeguard the future energy supply with a high share of fluctuating and decentralized renewable energy sources. At the same time, these grids will enable a reliable and affordable energy supply in the future. The objective is to provide new technologies and concepts for the security and quality of the energy supply in the transmission and distribution grids. To pursue this goal, the use of direct-current (DC) technology, based on power electronics, automation and communication technologies, plays an important role. Although DC technology is not yet established as a standard technology in the public electrical power supply system, its high potential has been widely recognized. The use of DC is an enabler to make the future energy supply system more economical than a system based on alternating-current (AC), because of its superior properties in handling distributed and fluctuation power generation. Indeed, DC connections are already the most cost-efficient solution in cases of very high-power long-distance point-to-point transmission of electricity or via submarine cables. The objective of the FEN Research Campus is now to achieve and demonstrate feasibility of DC as a standard solution for future electrical grids, as described in this study.

Download or read book HVDC FACTS for Grid Services in Electric Power Systems written by José M. Maza-Ortega and published by MDPI. This book was released on 2020-11-23 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electric power systems are headed for a true changing of the guard, due to the urgent need for achieving sustainable energy delivery. Fortunately, the development of new technologies is driving the transition of power systems toward a carbon-free paradigm while maintaining the current standards of quality, efficiency, and resilience. The introduction of HVDC and FACTS in the 20th century, taking advantage of dramatic improvements in power electronics and control, gave rise to unprecedented levels of flexibility and speed of response in comparison with traditional electromechanical devices. This flexibility is nowadays required more than ever in order to solve a puzzle with pieces that do not always fit perfectly. This Special Issue aims to address the role that FACTS and HVDC systems can play in helping electric power systems face the challenges of the near future.

Download or read book Dynamics and Control of High Voltage DC Grids written by Aleisawee M. Alsseid and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, HVDC based on VSC technology has become an area of growing interest because of its suitability in forming a transmission link for transmitting large amounts of power. M-VSC-HVDC has the possibility of being an attractive alternative to AC transmission in city centres, where underground cable transmission is preferred for safety and environmental reasons. Multi-terminal DC grids based on VSC-HVDC could be a competitive and attractive option, for many applications such as the integration of renewable energy and oil/gas platforms into the onshore grid system for supplying power to large metropolitan areas. Therefore, this thesis focuses on the control of M-VSC-HVDC and DC grids based on VSC. Firstly, a detailed non-linear model on a Power System Computer Aided Design/ElectroMagnetic Transients including Direct Current (PSCAD/EMTDC) simulation software for a 2-terminal HVDC based on VSC is presented in chapter 3. In the context of what is a complicated controller analysis and design task, the detailed analytical linear small signal state-space VSC-HVDC test system is modelled in MATLAB and is presented in chapter 3. The model should have good accuracy within the frequency range for the main HVDC control loop i.e. below 100Hz. Secondly, an eigenvalue stability study for control gains optimization is presented in chapter 4, with the use of the root locus technique. Very good matching accuracy is established in chapter 4 for the linear analytical model when compared with the detailed non-linear PSCAD test system models. A detailed comparison of the outer-loop control performance at the receiving end is presented in chapter 5. PID control (inner-loop) with d-axis current control and the DC voltage droop control (outer-loop) is confirmed to be adequate for advanced control design for an M-VSC-HVDC system and DC grid network. A 121st order MIMO small signal linearized dynamic model of a 5-terminal DC network is presented in chapter 6. The model accuracy is verified using detailed non-linear PSCAD simulation. The model has been used to study the effects of the DC voltage droop control on the dynamic and transient behaviour of the DC network. The work presented in this thesis therefore seeks to make a novel contribution by; presenting a detailed non-linear and linearized dynamic model of a DC grid based on a VSC test system. This model has significantly increased our confidence in the feasibility of DC grid networks. A higher order MIMO small signal linearized dynamic model of a 5-terminal DC network and an M-VSC-HVDC has been developed. They are the most detailed analytical models currently available. These models can be used for larger DC grids of any complexity. This thesis applies modeling knowledge boundaries to the automated building of an analytical model of a DC system and could be adapted for a very complex DC system. Two main issues regarding the implementation of the droop scheme have been investigated systematically by using the developed small signal model. Namely, the impacts and the selections of the DC droop gain and the cutoff frequency of the DC voltage droop filter. A systematic design of DC droop gains for DC grids has been presented. This thesis resolves a number of issues with developing DC grids and increases our confidence in building future complex DC transmission systems.

Download or read book Dynamics and Control of VSC based HVDC Systems written by Rodrigo Teixeira Pinto and published by LAP Lambert Academic Publishing. This book was released on 2012-05 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electricity transmission began with direct current. In 1880, Edison patented the first DC distribution system. That DC system was vital to broaden the use of his most famous invention, the electric lamp. However, at that time, low-voltage DC was proven inefficient. Despite the success of AC systems, the efforts for the development of practical high-voltage direct current transmission (HVDC) continued. The first HVDC transmission system was built in Sweden, in 1954, using mercury-arc valves. Nowadays, modern voltage-source converters (VSC) have smaller space requirements and improved reliability. VSC-HVDC has brought back the interest in the establishment of DC networks for applications such as DC supergrids and transnational networks for offshore wind farms. The goal of this work is to develop a more straightforward simulation model of VSC-HVDC systems; which can be inputted into simulation software packages and still provide realistic and reliable data on the system operation under all circumstances. The major contribution is the integration of the developed model, representing the whole DC transmission link, with the manifold control strategies possible for this new technology.

Download or read book HVDC and FACTS Controllers written by Vijay K. Sood and published by Springer Science & Business Media. This book was released on 2006-04-18 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: HVDC and FACTS Controllers: Applications of Static Converters in Power Systems focuses on the technical advances and developments that have taken place in the past ten years or so in the fields of High Voltage DC transmission and Flexible AC transmission systems. These advances (in HVDC transmission and FACTS) have added a new dimension to power transmission capabilities. The book covers a wide variety of topics, some of which are listed below: -Current Source and Voltage Source Converters, -Synchronization Techniques for Power Converters, -Capacitor Commutated Converters, -Active Filters, -Typical Disturbances on HVDC Systems, -Simulation Techniques, -Static Var Compensators based on Chain Link Converters, -Advanced Controllers, -Trends in Modern HVDC. In addition to EHV transmission, HVDC technology has impacted on a number of other areas as well. As an example, a chapter dealing with HVDC Light applications is included providing recent information on both on-shore and off-shore applications of wind farms.