Coordinated control method for primary frequency modulation and secondary frequency modulation of wind power plant

Abstract

The invention provides a coordinated control method for primary frequency modulation and secondary frequency modulation of a wind power plant. The method comprises the following steps of firstly, acquiring a grid-connected point frequency signal in real time through primary frequency modulation equipment, calculating primary frequency modulation power delta P1 when the frequency signal exceeds a dead zone range, transmitting the primary frequency modulation power delta P1 to an energy management platform, energy management platform adopting the coordinated control method of primary frequency modulation and secondary frequency modulation, and obtaining an active power given value of each wind turbine generator, wherein the wind turbine generator adopts a VSG technology of a self-adaptive inertia coefficient. According to the method, the power oscillation amplitude existing in the primary and secondary frequency modulation switching process of the centralized frequency modulation wind power plant can be effectively reduced, the local wind turbine generator set has the inertia damping characteristic of a simulated synchronous generator, the rotational inertia coefficient can be adaptively adjusted according to the change rate of the angular frequency, the overshoot of power change is effectively reduced, and the frequency abrupt change is relieved, and stability of the power generation system is improved.

Description

technical field [0001] The invention relates to a coordinated control method for primary frequency modulation and secondary frequency modulation of a wind farm, and belongs to the technical field of grid-connected operation control of wind farms. Background technique [0002] With the gradual increase in the penetration rate of new energy, the output space of conventional synchronous generators with moment of inertia and damping characteristics will inevitably be reduced, especially in northern winters. It has been operated in accordance with the "negative backup" start-up mode, a large number of synchronous generator sets have been replaced by new energy sources, the power structure has undergone major changes, and the resources that can be used for rapid frequency regulation of the power grid are gradually decreasing. At the same time, when the frequency of the power grid is disturbed due to emergencies such as DC blockage, machine cut-off, or load mutation, if the new ene...

AI Technical Summary

Problems solved by technology

At the same time, when the frequency of the power grid is disturbed due to emergencies such as DC blocking, machine cut-off, or load mutation, if the new energy power station does not have the primary frequency modulation capability to respond to system frequency changes and the damping characteristics similar to synchronous generators, it will further increase the system failure. Risk of expansion and blackout

Similar to the problem highlighted by the 8.9 blackout accident in the United Kingdom, in areas with a high penetration rate of wind power grid-connected power or a high proportion of EHVDC transmission in China, if there is an imbalance between power generation and load demand, frequency fluctuations will be triggered and a frequency regulation will be triggered. Power electronic control power sources such as wind farms or converter stations do not have an inertial response process and cannot actively support system frequency changes. A certain frequency change may trigger large-scale wind power off-grid, and some power grids will face collapse.

However, the above method is easy to cause power overshoot during the primary and secondary frequency modulation switching process, which will seriously affect the system stability.

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