Research on DC Voltage Control Strategies for Typical Four-Terminal HVDC System

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.

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Fei Chang ◽  
Zhongping Yang ◽  
Yi Wang ◽  
Fei Lin ◽  
Shihui Liu

The modular multilevel converter (MMC) is an emerging voltage source converter topology suitable for multiterminal high voltage direct current transmission based on modular multilevel converter (MMC-MTDC). This paper presents fault characteristics of MMC-MTDC including submodule fault, DC line fault, and fault ride-through of wind farm integration. Meanwhile, the corresponding protection strategies are proposed. The correctness and effectiveness of the control strategies are verified by establishing a three-terminal MMC-MTDC system under the PSCAD/EMTDC electromagnetic transient simulation environment.


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>


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