Wind power grid-connected low-frequency oscillation suppression method based on broadband and improved active disturbance rejection control

Abstract

The invention discloses a wind power grid-connected low-frequency oscillation suppression method based on broadband and improved active disturbance rejection control, and belongs to the field of powersystem stabilization and control. The method comprises the following steps: building an equivalent two-region system model of fan grid connection and a direct-driven wind power plant; obtaining a transfer function of inter-region tie line power fluctuation caused by wind power mechanical power fluctuation, considering the influence of wind shearing and tower shadow effects to enable the direct-driven wind turbine generator to become a forced power oscillation disturbance source, and obtaining a frequency band capable of exciting low-frequency oscillation between two equivalent regions of thedirect-driven wind power plant; designing a disturbance estimation module of the ADRC according to the frequency band, using the ADRC for replacing a traditional fan side q-axis current inner loop controller, thereby achieving the real-time compensation for the fan power low-frequency disturbance quantity, and achieving the suppression of wide-frequency-band low-frequency oscillation. The method is low in cost, good in inhibition effect and capable of adapting to changes of operation conditions.

Description

technical field [0001] The invention belongs to the field of power system stability and control, in particular to a wind power grid-connected low-frequency oscillation suppression method based on broadband and improved active disturbance rejection control. Background technique [0002] In recent years, the interconnection of large-scale power grids has made the scale of modern power systems larger and larger. The problem of weak or negative damping between and within large power grids has become very prominent in practical engineering. and an important factor in long-distance transmission capacity. As the renewable energy with the most development potential, wind power has developed rapidly and has received considerable attention in the energy strategies of various countries. When large-scale wind power is connected to the grid, the actual recording of the output power of the wind farm contains low-frequency periodic fluctuation components. The fluctuations are mainly cause...

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Problems solved by technology

The paper "Research on Forced Oscillation Suppression of Power System" proposed a forced disturbance source location and removal method based on active power fluctuation and voltage frequency fluctuation phase; however, the low-frequency periodic component in the output power of the wind farm is determined by the characteristics of the fan blade itself , cannot be removed; the paper "Analysis of Influencing Factors and Countermeasures for Low-frequency Oscillation of Resonance Mechanism Based on Machine-Network Coordination" proposes to use the governor power system stabilizer (GPSS) on the governor side to increase the system damping and reduce the amplitude of resonance oscillation, but only Relying on increasing damping to reduce the resonance amplitude does not respond to the disturbance source, and the suppression effect is limited; the paper "Research on Low-frequency Oscillation of Large-Scale Wind Power Grid-Connected System" uses energy storage devices to suppress resonance-type low-frequency oscillations, but the energy storage The installation requires a lot of manpower and material costs; the paper "Additional Damping Method for Suppressing Subsynchronous Oscillation of Double-fed Fan Stator-side Converter" introduces additional damping control in the stator-side and rotor-side converter control strategies respectively, by generating additional Torque is used to achieve oscillation suppression; however, changes in the operating conditions of the wind farm make the oscillation frequency have time-varying characteristics. Once the operating conditions of the system change, the parameters in the controller need to be reset to adapt to the change in oscillation frequency

In general, the existing suppression methods are all aimed at the problem of low-frequency oscillation caused by negative damping and the randomness of wind speed, and there is no related research on forced oscillation in a wide frequency band.

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