The research of the control strategies for 4-terminal VSC-HVDC system based on multi point voltage control and their implement

Author(s):  
Kaijian Ou ◽  
Haiping Guo ◽  
Xiaoyong Liu ◽  
Zexiang Cai ◽  
Lin Guan
Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2260
Author(s):  
Fan Cheng ◽  
Lijun Xie ◽  
Zhibing Wang

This paper investigated the characteristics of a novel type of hybrid high voltage direct current (HVdc) converter, which is composed by line commutated converter series with voltage source converter. The system and valve level control strategies are introduced, which can provide ac system voltage support. A novel filter design scheme composed by resonant filers for hybrid HVdc are also proposed, which can decrease the capacity of reactive power compensation equipment without deteriorate harmonic characteristics. The ac voltage of HVdc fluctuation level caused by transmitted power variation will be effectively reduced, with the coordination between filter design scheme and converter control. In addition, the influence of ac grid strength is also analyzed by equivalent source internal impedance represented by short circuit ratio (SCR). Finally, the +800 kV/1600 MW hybrid HVdc system connecting two ac grids under different SCR cases are studied, and the PSCAD/EMTDC simulation results have validated the effectiveness for proposed strategy.


2019 ◽  
Vol 371 ◽  
pp. 18-26 ◽  
Author(s):  
Amandeep Kaur ◽  
Hitesh C. Boghani ◽  
Edward M. Milner ◽  
Richard L. Kimber ◽  
Iain S. Michie ◽  
...  

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2407 ◽  
Author(s):  
Yu Wang ◽  
Yuewu Wang ◽  
Si-Zhe Chen ◽  
Guidong Zhang ◽  
Yun Zhang

The active power filter (APF) is a popular electrical device to eliminate harmonics in power systems. The rational design and effective control of DC-link capacitor voltage are important for implementing APF functions. In this study, the influences from the DC-link voltage on the APF compensating current characteristic and compensation performance are analyzed, and the reason to maintain DC-link voltage at a minimum value is investigated. On this basis, a simplified minimum DC-link voltage control strategy for APF is proposed. Compared with the existing DC-link voltage control strategies, the minimum DC-link voltage value in proposed strategy is only determined by the grid voltage and modulation ratio, reducing the calculation burden and the implementation difficulty in application, avoiding the interference from external parameters on the compensation effect. Additionally, the reference DC-link voltage varies at different values according to the grid voltage and modulation ratio. A shunt APF prototype is established and the experimental results verify the correctness and effectiveness of the analysis and proposed strategy.


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