Subsynchronous oscillation suppression method for doubly-fed wind farm grid-connected system based on virtual resistance

Abstract

The invention discloses a subsynchronous oscillation suppression method for a grid-connected system of a double-feed wind power plant based on virtual resistance, and the method comprises the steps: establishing an impedance model of the double-feed wind power plant according to the operating parameters and control parameters of the double-feed wind power plant and a circuit structure and parameters of the grid-connected system of the double-feed wind power plant; calculating the equivalent negative resistance amplitude of a rotor-side loop, and determining the rotor winding resistance and therotor-side converter equivalent resistance according to the impedance model of the double-feed wind power plant; obtaining a virtual resistance control coefficient according to the rotor winding resistance and the rotor-side converter equivalent resistance, and adjusting the size of the virtual resistance through the virtual resistance control coefficient. The method only needs to adjust the virtual resistance control coefficient to adjust the size of the virtual resistance so as to counteract the rotor winding resistance and the equivalent resistance of the rotor-side converter, and reduce the equivalent negative resistance amplitude of the rotor-side loop, thereby achieving the suppression of the subsynchronous oscillation of a system.

Description

technical field [0001] The invention belongs to the technical field of electrical engineering, and more specifically relates to a method for suppressing subsynchronous oscillation of a doubly-fed wind farm grid-connected system based on virtual resistance. Background technique [0002] In recent years, wind power-based new energy power generation has developed rapidly. North China, Northeast China and Northwest China, known as the "Three Norths", contain the most abundant wind energy resources in my country. In order to maximize the utilization of wind energy in the "Three Norths", large-scale long-distance DC transmission has become an effective solution. However, a series of subsynchronous oscillation problems appear in wind farms during large-scale wind power output, and these problems greatly restrict the ability of wind energy transmission in my country's "Three North" regions. [0003] A sub-synchronous oscillation accident occurred in a double-fed wind farm in the Gu...

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Problems solved by technology

[0006] Aiming at the above defects or improvement needs of the prior art, the present invention provides a subsynchronous oscillation suppression method based on virtual resistance for doubly-fed wind farm grid-connected system, thereby solving the existing subsynchronous oscillation suppression technology that increases the loss of power transmission , technical issues that increase the complexity and cost of system control

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