Abstract: The application relates to a method and system for a pilot directional protection of LCC-HVDC lines based on virtual grounding resistance The method comprises: Obtaining a conduction state information of a converter and characteristic parameters of a converter circuit within one commutation period after a fault occurs; according to the conduction state information and characteristic parameters, determining characteristic frequency of the circuit; according to the characteristic frequency and characteristic parameters, determining a virtual grounding resistance; according to the virtual grounding resistance, determining fault areas.

Abstract: Provided is a coal-containing wastewater spraying device for dust suppression during coal conveying, including a motor, a gland, a body seat, and an accelerator. The body seat includes a funnel-shaped cover, a first disc and a plurality of crushing plates. The accelerator includes a circular second disc. The end of an output shaft of the motor passes through the first disc to connect with the second disc. The cover is provided with a water retaining ring between the first disc and the second disc along its axial direction. The cover, the first disc, the second disc and the water retaining ring form a water inlet space.