Analysis of the Mechanism and Key Influence Factors of Short-Circuit Current Supply in VSC-HVDC to AC System

• Published in: 2018 International Conference on Power System Technology (POWERCON) pp. 2563 - 2570
• Main Authors: Xiaojun, Tang, Haifeng, Li, Qidi, Huo, Xiaodong, Zhang, Tao, Jin, Chunzheng, Tian, Yan, Xie, Meng, Chen
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.11.2018
• Subjects: Bridge circuits; Circuit faults; Power conversion; Reactive power; short-circuit current; Short-circuit currents; the fault of converter side; Transient analysis; transmission power; VSC-HVDC
• DOI: 10.1109/POWERCON.2018.8602196

VSC-HVDC applications are widely used and considered to be the development direction of the future power grid. However, the existing short-circuit current calculation standards and methods do not involve the impact of VSC-HVDC on short circuit current of AC system. Based on PSCAD, a two-level VSC-HVDC system is built. The transient characteristics of the short-circuit current provided by the VSC-HVDC system are studied. The influences of fault type, fault occurrence time, flexible dc transfer power, short circuit point location, control system parameters and output current limiting factors on short circuit current of the AC side injected by the VSC-HVDC are analyzed. The results show that compared with other short-circuit faults, the short-circuit current provided by VSC-HVDC is the largest when three-phase permanent short-circuit fault occurs; the short-circuit fault occurs when the current is positive or negative zero-crossing, and the short-circuit current provided by the VSC-HVDC is the largest; the short circuit provided by the VSC-HVDC current is positively related to transmission power; the farther the short-circuit point is located, the short-circuit current provided by the VSC-HVDC first decreases and then increases; the constant-voltage control proportional coefficient k p has little effect on the short-circuit current provided by the VSC-HVDC; the output current limiting section can significantly reduce the short circuit current provided by the VSC-HVDC.