Modeling, control and steady state analysis of back to back. Purpose selfcommuted voltage source converter vsc can significantly extend. This paper presents the performance analysis of vcs based hvdc transmission system. The igbtbased siemens hvdc plus is build out of selfcommutated systems with indirect voltage link voltagesourced converters, vsc and operates with the newest type of the modular multilevelconverter mmc, which is used in the ultranet project, and has a transmission capacity up to 2000 mw at a voltage of 500 kv dc. The enclosed cdrom contains the thesis report written in latex, adobe pdf formats, source codes, documents used throughout the thesis and simulink models. Figure 8 matlab simulink model of dc fault ridethrough capability of hvdc transmission systems based on hybrid voltage multilevel converter with ac side. Simulation results show that the proposed multiterminal vsc hvdc was able to maintain. A three terminal vsc hvdc was modeled and simulated in matlab simulink software. High level controllers are responsible to regulate dc voltage, active power, reactive power, ac voltage and the frequency of the system 10. The objective is to understand the control structure of the vsc hvdc system and establish the tuning criteria for the proportionalintegral pi control of the converter controllers. Simulation of vsc based hvdc transmission system under. A description of the control system is provided in the vsc based hvdc link case study of the users manual. Pdf matlabsimulink model for hvdc fault calculations.
The converters can be connected in back to back configuration or at either end of a transmission line or cable as schematically shown in figure 1. Moreover, to confirm the adequacy of the obtained results, the comparison with a detailed voltage source converter hvdc model simulink matlab and eurostag software are introduced. Pdf modelling, control design and analysis of vsc based hvdc. The objective is to understand the control structure of the vschvdc system and.
Hvac 3phase lower transmission loss because of no reactive loss lower insulationclearance of conductor dc voltage is about 71% of the ac peak voltage. Voltage source converter based hvdc vsc hvdc system is the best option for realizing future multiterminal hvdc system to integrate bulk amount of energy over long distances to the ac grid. A vsc hvdc link connecting the simplified gb power system model to another ac grid is used for simulation and experimental verification of the fast frequency control scheme. Pdf the development of power semiconductors, specially igbts has led to the small power hvdc transmission based on voltage source converters vscs. The applications of vsc hvdc for hydropower unit connection were rarely discussed, because the capacity and voltage rating of vsc hvdc had been thought as a major limitation for transmission level application. An infrequent power infeed loss 1800 mw is simulated to assess the performance of the frequency support scheme presented in section iii. Simulations were carried out using matlab simulink. Two technologies offered by the manufacturers are the hvdc light and the hvdc. Load the saved model in step 2 above in the selected older simulink version.
Abstract high voltage direct current system based on voltage source converters vsc hvdc is becoming a more effective, solution for long distance power transmission especially for offshore wind plants and supplying power to remote regions confronting with an increasing demand of power, there is a need to explore the most efficient and reliable bulk power transmission system. Vsc hvdc with dc voltage droop control thesis part2 youtube. This book looks at the control of voltage source converter based high voltage direct current vsc hvdc. The design and experimentally controllers of vsc in lab scaled test, matlab simulink program were performed vsc hvdc transmission system, simulation in.
Jan 01, 2014 for validation of the model thus developed, simulations were performed using the data of the abb openaccess benchmark model abb, 2007. Modeling, control and steady state analysis of back to. Pdf modelling of a vscbased multiterminal hvdc network for. Simulation model with mw pv stations and vsc hvdc. Interconnection of weak power system by vschvdc using fuzzy. Design and implementation of multiterminal vsc hvdc. Section iv presents the vector control method for vsc hvdc. Top pdf voltagesourceconverter highvoltage dc vschvdc. System description the set up for the comparative study of the dynamic behaviour of a direct and vsc hvdc grid connected dfig wind farm is shown in figures 5 and 6 respectively. Simplified modeling of vschvdc in power system stability. A feedback linearization based control strategy for vschvdc.
Hvdc disadvantages hvdc is generally less reliable and has lower availability than hvac. The pulsewidth modulation pwm based voltagesource converter vsc is an emerging technology for hvdc transmission 16, 17. Following this the offshore vsc is deblocked and the offshore grid gets. Vsc based hvdc which uses twelve pulse three level con verter topology. Modelling, control design and analysis of vsc based hvdc. For one station on the offshore wind farm side operates as the rectifier station. Development, calibration and simulation of generic vschvdc. It is based on the voltage source converter, where the valves are built by igbts and pwm is. Pdf the trend in semiconductor developments has made the highvoltage. Vschvdc station, a complete lcc ones needs double the space 7. Vsc based hvdc system file exchange matlab central. Top pdf reactive power control and harmonic elimination in. However, in recent years, the vsc hvdc technology has been developed significantly and its application has been.
Mar 23, 2017 vsc hvdc with dc voltage droop control thesis part2 chandra shekhar sharma. Vsc hvdc grid features a highly manageable system, active power imbalances will be filtrated within the hvdc grid, therefore, eliminating. The vsc hvdc thus, gets charged to the operating voltage of 150kv. Vsc hvdc system is provided with detailed explanation of each element associated with thesystem. Pdf control and analysis of vsc based high voltage dc. The power system and the control system are both discretized for a sample time ts50 us. Matlab simulink are carried out and results are presented to test the robustness of the designed controller. Furthermore, it addresses dc fault characteristics and their transients.
The vsc based hvdc transmission system mainly consists of two converter stations connected by a dc cable. Pscad and simulink are graphical tools that can be used for simulation. Fast frequency support control in the gb power system. Fast frequency support control in the gb power system using vsc. The active power transfer capability of the dc link is assumed mw. A study of hvdc circuit breakers and matlabsimulink based. Lcc needs a highly stable ac grid while vsc is capable of operating in very weak or even passive ac systems. To develop multiterminal vsc hvdc technology it is necessary to study the behavior and interaction of vsc controls. Design and implementation of voltage source converters in.
Components of vsc hvdc system vsc hvdc is a new dc transmission system technology. The increasing rating and improved performance of selfcommutated semiconductor devices have made possible high voltage dc hvdc transmission based on voltagesourced converter vsc. The example described in this section illustrates modeling of a forcedcommutated voltagesourced converter highvoltage direct current vsc hvdc transmission link. Steady state fault analysis of vsc hvdc transmission system. One of the advantages of applying a voltagesource converter vsc based hvdc system is its potential to be connected to very weak ac systems where the. Comparative evaluation between direct connected and vschvdc. In this paper, the pscad emtdc simulation tool is used to study the dynamic recovery performance of vsc hvdc system for several different var compensating devices in vsc hvdc inverterfixed capacitor fc, static var compensator svc, and static synchronous compensator statcom when vsc hvdc is subject to various faults, including three phase groundings, single phase grounding and three phase breakings.
Simulation of hvdc system in simulink and fault analysis. Frequency control of island vschvdc links operating in. In this paper a 75km long vsc hvdc system is simulated for various faults on the acside of the receiving station using matlab simulink. Voltage source convertesvsc, hvdc, parameter optimization, eigenvalue. A feedback linearization based control strategy for vsc. All simulations are performed using the 2015b version of matlabsimulink. Simulation of vsc based hvdc transmission system under fault. The igbtbased siemens hvdc plus is build out of selfcommutated systems with indirect voltage link voltagesourced converters, vsc and operates with the newest type of the modular multilevelconverter mmc, which is used in the ultranet project, and has a transmission capacity up to 2000 mw at a. Modelling, control and simulation of lcc hvdc systems for. Section iii provides the operating principle of vsc hvdc. A comparative study on control loop interactions in vschvdc. Modelling and simulation of vschvdc connection for. Jul 10, 2015 this comprehensive reference guides the reader through all hvdc technologies, including lcc line commutated converter, 2level vsc and vsc hvdc based on modular multilevel converters mmc for an indepth understanding of converters, system level design, operating principles and modeling. Recently, studies on hvdc circuit breaker cb prototypes have shown successful take a look at results.
Modelling of multiterminal vschvdc links for power flows and. Vsc hvdc system consists of two control systems, a high level and a low level control. Apr 12, 2020 voltage source converter vsc based multiterminal highvoltage direct current hvdc systems received widespread attention throughout the world for grid integration of renewable energy resources in recent years. Matlab simulink system identification toolbox and a transfer function.
Volume 3 issue 1 international journal of engineering. Components of vsc hvdc system and its operationvsc hvdc is a new dc transmission system technology. Development, calibration and simulation of generic vsc. For one station on the offshore wind farm side operates as. Vsc hvdc system modeling and validation april 18th, 2019 vsc hvdc system modeling and validation robert rogersten masters degree project stockholm sweden 2014 xr ee eps 2014 003 2 high voltage direct current transmission and control 9 an extension of matlab has been mentioned pscad and simulink are graphical tools that can be used for. Index terms high voltage transmission, frequency dc. Simulation results show that the proposed multiterminal vsc hvdc. A description of the control systems is provided in the hvdc transmission system case study of the users manual. Adobe pdf formats, source codes, documents used throughout the thesis and simulink models.
In contrast to the conventional thyristorbased hvdc system, a vsc hvdc system has the potential to be connected to very weak ac systems, as well as the capability to generate or consume reactive. Both technologies have many features in common but also have key difference. This paper assesses its dynamic performance during steadystate and network alterations, including its response to ac and dc side faults by using mat lab simulink. Vsc controllers for multiterminal hvdc transmission system. Design and implementation of voltage source converters in hvdc. Additionally, tools are developed for the steadystate and dynamic simulation of power systems with vsc hvdc connections. Interconnection of weak power system by vschvdc using. High voltage direct current hvdc technology has been widely recognized advanced in power transmission. Therefore, they can be used to simulate multiterminal vsc hvdc systems.
This master thesis present the modelling, control and simulation of a lcc hvdc linecommutated converter, high voltage direct current, which is the most prevalent type of hvdc technology in current transmission grids. Then the onshore grid side vsc is deblocked and the gate pulses are applied. Section v presents the modeling of vsc hvdc system. The controller has been proposed by using pq control and feedforward decoupled current control algorithm. Voltage margin method has been used for reliable operation of the hvdc system without the need of communication. The vsc hvdc link comprises the mainland vsc, the island vsc and two 320 kv, 300 km long submarine cables. The main contribution of the models is that they are valid for every topology of the dc grid. Fast frequency support control in the gb power system using. In this paper, the pscad emtdc simulation tool is used to study the dynamic recovery performance of vsc hvdc system for several different var compensating devices in vsc hvdc inverterfixed capacitor fc, static var compensator svc, and static synchronous compensator statcom when vsc hvdc is subject to various faults, including three phase groundings, single phase grounding and three phase. Feb 17, 2014 vsc hvdc system modeling and validation robert rogersten masters degree project stockholm, sweden 2014 xreeeps 2014. In order to design, control and operate hvdc systems, along with on site experiments, system studies using simulation platforms become necessary. The example described in this section illustrates modeling of a forcedcommutated voltagesourced converter highvoltage direct current vsc hvdc. Mainly due to the extra conversion equipment and maintenance difficulty. North sea offshore modelling schemes with vschvdc technology.
Acknoledgements the authors are especially grateful to their supervisors remus teodorescu, pedro rodriguez. Vsc hvdc system modeling and validation robert rogersten masters degree project stockholm, sweden 2014 xreeeps 2014. This paper presents a comparative performance analysis of different vsc based outer control and inner current controllers for the multiterminal hvdc system. Modelling and simulation of vschvdc connection for offshore. Control of vsc based hvdc transmission system for offshore wind power plants master thesis conducted by group wps 4 1050. Section vi provides the simulation results of the proposed system. Fault current characterisation in vscbased hvdc systems. The simulink model considered for the simulation shown in fig. An overview to restate the obvious, both converters of vsc hvdc one operating as a rectifier and the other as an inverter are connected to ac networks at both ends of the line. Comparative evaluation between direct connected and vsc. Simulation results using matlabsimulink demonstrate that the closedloop combination of the ac voltage and the dc voltage controllers results in the highest. Direct current vsc hvdc systems for power system analysis.
Vsc hvdc simulink model file explore our projects manitoba hydro international. Multi terminal vsc hvdc connection scenario 1 the multiterminal vsc hvdc network shown in figure 3 is implemented to investigate system behaviour in the event of an ac fault, and also during a sudden loss of the converterdc link cable. An analysis of the commutation process is performed, illustrating the base theory behind an lcc. Hvdc circuit breakers are difficult some mechanism must be included in the circuit breaker to force current to zero. As it is a relatively new technology when compared to the more mature classic hvdc, many studies are aimed at operation and stability of vsc hvdc interconnecting ac grids. Save it as the required older version 2015a model by choosing the correct save as type option through the filesaveas menu or through fileexport model toprevious version. It is based on the voltage source converter, where the valves are built by igbts and pwm is used to create the desired voltage waveform. Modeling and control of vschvdc links connected to. Voltage source convertes vsc, hvdc, parameter optimization, eigenvalue.
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