Method for initiating flexible DC transmission system under isolated island condition

    公开(公告)号:US11329486B2

    公开(公告)日:2022-05-10

    申请号:US16607847

    申请日:2018-04-27

    IPC分类号: H02J3/36 H02J3/38

    摘要: During initiation under an isolated island condition, the amplitude of a voltage reference wave output generated by a flexible DC transmission control and protection system is in a segmented mode, wherein a first segment of the reference wave amplitude begins at zero or a fixed value Ux and rapidly increases to Ua kV at a rate of a kV/s, avoiding a low output voltage reference wave and high error and harmonic content of a sampled voltage and current. A second segment increases to Ub kV at a rate of β kV/s, a third segment increases to Uc kV at a rate of γ kV/s, and the Nth segment increases to a rated voltage of UN kV at a rate of ε kV/s, thereby achieving non-disturbance and shockless initiation of a flexible DC transmission system under an isolated island condition.

    Fault switch configuration and clearing method in flexible DC converter station

    公开(公告)号:US10923906B2

    公开(公告)日:2021-02-16

    申请号:US16500189

    申请日:2018-05-22

    摘要: A fault switch configuration and clearing method in a flexible DC converter station, the flexible DC converter station is configured with a grid side switch and a valve side phase-split switch in the converter station. When a fault occurs, a faulty phase and a non-faulty phase are detected and identified by means of differential protection or low voltage overcurrent. An alternating current zero crossing condition is created by means of firstly turn off the non-faulty phase valve side phase-split switch and the grid side switch, thereby cutting off the faulty phase, disconnecting the connection between a power supply and a fault point, and achieving the clearing for faults. The described fault-clearing method is simple and practical, highly reliable, and connection between the fault point and the power supply is quickly and effectively cut; converter station equipment is effectively protected, and further expansion of the fault is avoided.