Wind power plant synchronous oscillation cutout method based on negative damping contribution

Abstract

The present invention provides a wind power plant synchronous oscillation cutout method based on negative damping contribution. The method comprises the steps of: collecting three-phase voltages and three-phase currents of each 35kV electric wire and an outgoing line of a booster station in a wind power plant to obtain a time-domain sequence; performing selectivity filtering of the time-domain sequence to filter power frequency components and high-frequency components and obtain subsynchronous / hypersynchronous oscillating component sequences therein; performing feature information calculationfor the subsynchronous / hypersynchronous oscillating component sequences to obtain the subsynchronous / hypersynchronous equivalent impedance; and performing ranking of the impedance of each electric wire according to the electrical resistance properties, and cutting out the electric wire having the largest negative damping contribution according to the order until the electric wires all provide positive resistances. The method can cut out the wind turbine generators generating the oscillation in a refined mode by steps according to the contribution to the subsynchronous / hypersynchronous oscillation by each electric wire, and is suitable for effective protection and control when the wind turbine generators are subjected to large-scale grid connection to generate the subsynchronous / hypersynchronous oscillation.

Description

technical field [0001] The invention belongs to the technical field of power system monitoring and control, and in particular relates to a method for removing subsynchronous oscillations of wind farms based on negative damping contributions. Background technique [0002] Different from traditional generators, new energy generation such as wind and light are integrated into the grid through power electronic devices, and its multi-time-scale control characteristics interact with the characteristics of the grid itself, which may cause sub-synchronization into the harmonic frequency band, resulting in Control instability and oscillation problems that are not found in traditional power systems. In recent years, this kind of problem has gradually become prominent in the power grid, and the scope of influence is wider and wider, and the consequences are more and more serious. In 2014, more than 200 Hz harmonic oscillation occurred in the offshore wind farm in northern Germany thro...

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Problems solved by technology

More importantly, the formation mechanism of this subsynchronous oscillation is inconsistent with that of the traditional power system. It is caused by the subsynchronous harmonics introduced by the collection of a large number of new energy sources. The existing monitoring, protection and control methods are no longer applicable.

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