Results 11 to 20 of about 103 (62)
Gaoya dianqi, 2016 针对多馈入直流系统故障后难以快速恢复的问题,提出了一种基于模糊理论,并融合多馈入直流特性的自适应变结构VDCOL控制策略。该控制方法将模糊控制的非线性特性与VDCOL控制机理有效结合,同时将多条直流自身的强度和相互作用考虑在内,根据电压大小及其恢复水平对直流电流进行动态控制,协调系统的电压和功率恢复。仿真结果表明:该控制方法能够有效控制恢复期间的无功需求,抑制后续换相失败发生,加快系统的恢复,保证系统的安全稳定运行。
胡松伶, 王渝红, 李兴源
doaj +1 more source
A novel low-voltage current-limiting control strategy with improved voltage compensation
Energy Reports, 2023 By optimizing the design of the conventional low-voltage current limiting controller (VDCOL), the continuous commutation failure on the receiving end of the traditional LCC-HVDC transmission system is effectively suppressed.
Haitao Wu, Yunbin Li, Zhihe Wang
doaj +1 more source
IET Generation, Transmission &Distribution, Volume 17, Issue 23, Page 5124-5134, December 2023., 2023 Decision tree (DT) model is adopted to extract the mapping relationship between transient overvoltage and massive electrical quantities of power grids. The common DT algorithm is transformed by modifying the error weight assignment, which reflects the error tolerances for different actual overvoltage regions. To compensate for potential inaccuracies in
Zhe Zhang +4 more
wiley +1 more source
IET Generation, Transmission &Distribution, Volume 17, Issue 16, Page 3638-3647, August 2023., 2023 This paper proposes an autonomous master‐slave control strategy suitable for the cascaded multi‐terminal UHVDC (CMT‐UHVDC) system to maintain voltage balance without real‐time communication between high‐end and low‐end valves. Several working conditions and the practical influence of sampling deviation on the control performance based on the ...
Sihang He +4 more
wiley +1 more source
IET Generation, Transmission &Distribution, Volume 17, Issue 8, Page 1902-1917, April 2023., 2023 An analytical expression among the dc current, ac voltage, and extinction angle of both layers is newly derived to find the dominant factors to the CCF. To improve the calculation accuracy, a three‐point sampling function using Newton interpolation is newly proposed to predict the dc current.
Shenghu Li, Yikai Li
wiley +1 more source
Analysis and prevention of commutation failure caused by HVDC rectifier AC faults
IET Generation, Transmission &Distribution, Volume 16, Issue 7, Page 1416-1424, April 2022., 2022 Abstract Earlier works have reported that rectifier AC faults also can cause commutation failure during fault‐off recovery process. Whereas the occurrence of CF is merely ascribed to inverter AC faults in conventional wisdom. Note that the existing CF mitigation approaches are designed mostly by the evolution of inverter electrical quantities, which ...
Sheng Lin, Yuqing Lei, Jian Liu, Lei Liu
wiley +1 more source
IET Renewable Power Generation, Volume 16, Issue 6, Page 1148-1158, 27 April 2022., 2022 Abstract The hybrid HVDC with cascaded multi‐infeed MMC inverters will be put into reality soon in China, but its MMC inverter in constant DC voltage control would become a rectifier when disturbance happens. Thus, to solve such problem and enhance the stabilities, the adaptive droop control is proposed for MMC inverters and a hierarchical coordinated ...
Jingbo Zhao, Yan Tao
wiley +1 more source
IET Generation, Transmission &Distribution, Volume 16, Issue 3, Page 591-602, February 2022., 2022 Abstract Concerning the transient power angle stability problem in AC/DC inter‐connected system caused by DC line grounding fault, a transient stability analysis method based on the stability margin of dynamic energy is proposed. First, the analytical expressions of the dynamic energy function before alpha retard, during alpha retard and after alpha ...
Jing Ma +3 more
wiley +1 more source
International Transactions on Electrical Energy Systems, Volume 2022, Issue 1, 2022., 2022 Commutation failure (CF) is an inherent drawback of line‐commutated converter high‐voltage DC (LCC‐HVDC) system. And CF prevention (CFPREV) control is widely applied in UHVDC lines to mitigate the subsequent CF. However, the formation of a multi‐infeed UHVDC system induces power exchange and voltage interaction between AC buses during the transient ...
Wei Yao +7 more
wiley +1 more source
Electronics Letters, Volume 57, Issue 5, Page 229-231, March 2021., 2021 Abstract The hybrid high‐voltage direct current (HVDC) with cascaded multi‐infeed MMC inverters is proposed in recent years, and it will be put into reality in near future. But the commutation failure of the line‐commutated converter (LCC) inverter will make the whole HVDC system to be blocked because the DC fault current could reach beyond the safety ...
Qin Jiang +3 more
wiley +1 more source