A method for subsynchronous oscillation suppression of a flexible direct current power transmission system

Abstract

The present application belongs to the flexible DC power transmission system based on voltage source converter, and particularly relates to a method for suppressing subsynchronous oscillation of the flexible DC power transmission system. The method comprises the following steps: S1: obtaining the d-axis voltage and q-axis voltage of the AC side of the flexible DC converter station and the d-axis current and q-axis current injected into the converter station; S2: obtaining the d-axis component and q-axis component of the temporary value of the compensated virtual current by phase compensation simulation of the obtained d-axis and q-axis currents; S3: limiting the amplitude of the temporary value of the virtual current to obtain the final value of the phase-compensated current; and S4: replacing the actual current in the inner loop control with the final value of the current, and the controller completes the calculation according to the replaced current and delivers the voltage reference value command to the valve control link to realize the suppression of subsynchronous oscillation. The method can effectively suppress the oscillation after the occurrence of the subsynchronous oscillation phenomenon of the system, and can effectively reduce the risk of the occurrence of the subsynchronous oscillation of the system if the strategy is always put into operation.

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