scholarly journals Analysis of Propagation Delay for Multi-Terminal High Voltage Direct Current Networks Interconnecting the Large-Scale Off-Shore Renewable Energy

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2115 ◽  
Author(s):  
Muhammad Nadeem ◽  
Xiaodong Zheng ◽  
Nengling Tai ◽  
Mehr Gul ◽  
Sohaib Tahir

Voltage-source-converter-based multi-terminal high voltage direct current (MTDC) networks are extensively recognized as a viable solution for meeting the increasing demand of electrical energy and escalating penetration of renewable energy sources. DC faults are major limitations to the development of MTDC networks. The analysis of variable constraints has become mandatory in order to develop a reliable protection scheme. This paper contributes in assessing the propagation delay with the analytical approximation in MTDC networks. The propagation delay is analyzed in the time domain by taking only the forward traveling wave into account and considering the initial voltage step of magnitude at the fault position. Numerous simulations were carried out for different parameters and arrangements in Power System Computer Aided Design (PSCAD) to explore the proposed expressions. The results accurately depicted the time development of fault current. The results obtained from the real-time digital simulator (RTDS) confirmed that the proposed approach is capable of evaluating propagation delay in MTDC networks. Moreover, the influence of fault resistance is also taken into account for investigating its effect on the system parameters.

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 474
Author(s):  
Junxi Wang ◽  
Qi Jia ◽  
Gangui Yan ◽  
Kan Liu ◽  
Dan Wang

With the development of large-scale new energy, the wind–thermal bundled system transmitted via high-voltage direct current (HVDC) has become the main method to solve the problem of wind power consumption. At the same time, the problem of subsynchronous oscillation among wind power generators, high-voltage direct current (HVDC), and synchronous generators (SGs) has become increasingly prominent. According to the dynamic interaction among doubly fed induction generators (DFIGs), HVDC, and SGs, a linearization model of DFIGs and SGs transmitted via HVDC is established, and the influence of the electromagnetic transient of wind turbines and HVDC on the electromechanical transient processes of SGs is studied. Using the method of additional excitation signal injection, the influence of the main factors of DFIG on the damping characteristics of each torsional mode of SG is analyzed, including control parameters and operation conditions when the capacity of HVDC is fixed. The mechanism of the negative damping torsional of SGs is identified. A time-domain simulation model is built in Electromagnetic Transients including DC/Power Systems Computer Aided Design (EMTDC/PSCAD) to verify the correctness and effectiveness of the theoretical analysis.


Author(s):  
Mario A. Rios ◽  
Maria F. Perez

<p>Planning of high voltage direct current (HVDC) grids requires inclusion of reliability assessment of alternatives under study. This paper proposes a methodology to evaluate the adequacy of voltage source converter/VSC-HVDC networks. The methodology analyses the performance of the system using N-1 and N-2 contingencies in order to detect weaknesses in the DC network and evaluates two types of remedial actions to keep the entire system under the acceptable operating limits. The remedial actions are applied when a violation of these limits on the DC system occurs; those include topology changes in the network and adjustments of power settings of VSC converter stations. The CIGRE B4 DC grid test system is used for evaluating the reliability/adequacy performance by means of the proposed methodology in this paper. The proposed remedial actions are effective for all contingencies; then, numerical results are as expected. This work is useful for planning and operation of grids based on VSC-HVDC technology.</p>


Author(s):  
Araitz Iturregi ◽  
Agurtzane Etxegarai ◽  
D. Marene Larruskain ◽  
Pablo Eguia ◽  
Oihane Abarrategui

Goi-tentsioko korronte zuzeneko (ingelesez, High Voltage Direct Current HVDC) garraio-sistemak gero eta garrantzitsuagoak dira sistema elektrikoan, onura ekonomiko eta teknikoak direla eta. Hala ere, akatsen bat gertatzen denean, korrontea eteteak oraindik ere erronka izaten jarraitzen du HVDC sareetan. Desiragarriak ez diren korronteak eteteko, korronte zuzeneko etengailuak erabil daitezke, baina horien gaitasuna mugatua da. Egoera hala izanik, akats-korronteen mugagailuak (ingelesez, Fault Current Limiter FCL) dira proposamenik egokiena akats-korronteak maneiagarriagoak diren balioetara txikitzeko; hartara, sistema elektrikoaren garraio-ahalmena handitu daiteke, ekipamendua aldatu beharrik gabe. Sarean aldez aurretik legokeen ekipamendua gai izango litzateke korronte berriak kudeatzeko eta sistema era eraginkorrean babesteko FCLen erabilpenaz. Artikulu honetan, FCL tresnen ezaugarri orokorrak eta sailkapena aurkezten dira. Ondoren, egoera solidoko FCLa erabili da maila anizkoitzeko bihurgailudun (ingelesez, Modular Multilevel Converter MMC) VSC-HVDC (ingelesez, Voltage Source Converter) sistema batean, eta horren jokaera azaltzen da simulazio bidez.


2014 ◽  
Vol 521 ◽  
pp. 222-228
Author(s):  
Kai Wang ◽  
Hai Shun Sun ◽  
Yu Hua ◽  
Yuan Liu ◽  
Wei Xing Lin ◽  
...  

The continuous development of alternative energy has put forward higher requirement for electricity transmission. To cope with its fluctuation characteristics, high voltage direct current (HVDC) technology has received more attention. Voltage Source Converter (VSC) based Multi-Terminal High Voltage Direct Current (MTDC) represents the future trend of HVDC technology. This paper mainly focuses on the control strategies of a four-terminal VSC based MTDC power transmission system. The operation characteristic of the system was studied, and the proposed two control strategies, master-slave control strategy and DC voltage droop control strategy, were verified through simulations. The latter control strategy was proved to be performing well under various conditions, including converter station disconnection and faults at AC side of the converter.


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