DC HYBRID TRANSMISSION SYSTEM WITH COUNTABLE ON AND POWER FLOW TRANSFER CONTROL IN OPPOSITE DIRECTION Russian patent published in 2019 - IPC H02H7/26 

FIELD: electrical engineering.

SUBSTANCE: field of application: electrical equipment. DC transfer system with a cross-connect contains an LCC converter and a VSC converter in counter-switching, and a first mode switch, a second mode switch, a third mode switch and a fourth mode switch. In this case, the first mode switch is connected to the first AC system and the LCC converter; the second mode switch is connected to the first AC system and the VSC converter; the third mode switch is connected to the second AC system and the VSC converter; and a fourth mode switch is connected to the second AC system and the LCC converter. When transmitting power in the forward direction, the first mode switch and the third mode switch are closed; and when power is transmitted in the opposite direction, the second mode switch and the fourth mode switch are closed. In this way, it is ensured that the VSC converter always performs an inversion operation in either power direction, so as to avoid the problem of potential commutation disturbance for the LCC converter during the inversion operation. Also, a method is proposed for quickly controlling the transmission of power flow in the opposite direction of a hybrid DC transmission system with counter-switching.

EFFECT: there are no commutation disturbances on the inverter side, both in the case of transmission of power flow in the forward direction and in the case of transmission in the opposite direction.

5 cl, 8 dwg