The invention discloses a modular direct-current
grid connection topology comprising an energy storing device for a
wind power station group. The modular direct-current
grid connection topology comprises a first convertor
station, a second convertor
station and a third convertor station, wherein the first convertor station is positioned near the
wind power station group; the alternating-current
bus end of the first convertor station is connected with a
wind power station; the alternating-current
bus end of the second convertor station is connected with the energy storing device; the direct-current
bus end of the second convertor station is connected with the first convertor station through a direct-current bus; the alternating-current bus end of the third convertor station is connected with a receiving end
power grid; the direct-current bus end of the third convertor station is connected to the direct-current bus; the first convertor station is used for transmitting power of each wind
power station to the direct-current bus; the third convertor station is used for controlling the
voltage of the direct-current bus to be constant, and transmitting power emitted by each wind
power station to the receiving end
power grid; and the energy storing device is used for absorbing or transmitting power to stabilize the fluctuation of the wind power. The wind power stations in the
system are not in alternating-current
interconnection with a local
power grid or other wind power stations, so that the influence range of an alternating-current fault can be limited, the wind power short fluctuation can be stabilized, and the
system stability can be improved.