The invention discloses a starting method of a high-
voltage direct current transmission system. If the communication between stations fails and a frequency
control function operates, a current instruction at a
rectifier side is set to be 1.0pu, and meanwhile, the
voltage reference value compensation of a
constant voltage controller at the
rectifier side is cancelled, the
voltage reference value compensation is added at an
inverter side, and
voltage reference values at two sides are set; the
inverter side is unlocked, and the
inverter side is forced to work in a constant
extinction angle
control mode; the
rectifier side is manually unlocked, a shift phase command is released after the rectifier side is unlocked, and the
constant voltage controller at the rectifier side operates when the output of a
constant current controller at the rectifier side drops to be equal to the output of the
constant voltage controller; the
direct current voltage at the inverter side is detected, and the current margin is compensated; and the inverter side enters a
constant current control mode, the current is controlled at the minimum operating current, and then the starting process is finished. Through the starting method, the controllers at the two sides can be coordinated to work under the condition that the communication between stations fails, and the constant
voltage control at the rectifier side and the
constant current /
power control at the inverter side after starting are realized.