A HV/UHV DC Transmission Control Strategy Switching Method

Abstract

The invention discloses a switching method of high-voltage / extra-high-voltage direct-current power transmission control strategies. The method includes: a frequency control function state is acquired, if a frequency control function inputs and inter-station communication states change from normal into fault, a rectifying station uses the output of a fixed-current controller to limit the output of a fixed-voltage controller, and an inverter station uses the output of the fixed-voltage controller to limit the output of the fixed-current controller; if the inter-station communication states change from fault to normal, the rectifying station uses the output of a fixed-voltage controller to limit the output of the fixed-current controller, and the inverter station uses the output of the fixed-current controller to limit the output of the fixed-voltage controller; if the frequency control function quits, the rectifying station keeps fixed-current control unchanged, and the inverter station keeps fixed-voltage control unchanged. By the method, the control strategies can be switched according to the inter-station stages, and undisturbed switching of direct-current power transmission can be achieved when the control strategies change.

Description

technical field [0001] The invention belongs to the fields of high-voltage direct current transmission and ultra-high voltage direct current transmission, and particularly relates to a method for switching control strategies of a high-voltage direct current transmission system. Background technique [0002] The HVDC power transmission system includes a rectifier station and an inverter station, both stations are equipped with constant current controllers (such as figure 1 shown) and constant voltage controllers (such as figure 2 shown), where the logic principle of the constant current controller is: the current measurement value minus the current command value to obtain the deviation value, the deviation value is input into the proportional integral link, and the obtained output is subjected to the limiting link to obtain the constant current controller Output, where the current command value is the sum of the current command reference value and the current margin compens...

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Problems solved by technology

If no proper switching method is adopted, the control system of the two stations can self-adjust to realize the above-mentioned control strategy transformation, which will lead to the failure of the switching and the excessive dynamic disturbance of the system during the switching process, the switching duration is too long, and even the control systems of the two stations are unstable. and crash

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