Real-time stability control device suitable for new energy grid-connected system

Abstract

The invention discloses a real-time stability control device suitable for a new energy grid-connected system. The device is installed between a new energy power station and a to-be-accessed power system. The hardware part consists of circuit modules such as a series voltage injection module, a parallel current injection module, an electric quantity acquisition module, a real-time controller moduleand the like, and the software part consists of modules such as a sweep frequency harmonic calculation module, a real-time impedance analysis module, a weak damping region judgment module, an impedance correction calculation module, an oscillation signal extraction module, a compensation signal calculation module and the like. The device calculates impedance of a new energy power station and an electric power system in real time through continuous sweep frequency harmonic signal injection, determines the weak damping area of the system on line, corrects impedance of the system in a full frequency band in real time through injection of a series compensation signal and a parallel compensation signal, and enables the system to be always kept stable. The device can effectively prevent broadband oscillation when new energy is merged into a power system, has good real-time performance, and does not need to change a control mode of a grid-connected converter in a new energy power station.

Description

technical field [0001] The invention relates to the field of stability control of new energy grid-connected systems, in particular to a real-time stability control device suitable for new energy grid-connected systems. Background technique [0002] New energy represented by wind power and photovoltaics has developed rapidly in recent years, and my country's total installed capacity of new energy has ranked first in the world. New energy mostly uses grid-connected converters to connect to the grid. Due to the advantages of high flexibility and fast response in grid-connected control, it provides convenience for new energy to be integrated into the grid, and its penetration level in the power system is also increasing. At the same time, the characteristics of "low inertia, nonlinearity, and multiple time control scales" of the grid-connected converter also make the components in the new energy grid-connected system more complicated to interact, and the system oscillation frequ...

AI Technical Summary

Problems solved by technology

The existing method mainly realizes the impedance reshaping of the converter through the control parameters, and the adjustment space of the control parameters is small

[0005] 2) Most of the existing methods reshape the impedance of the converter after the oscillation occurs, and the real-time performance is not high

[0006] 3) The existing method needs to reshape the impedance of all converters in the new energy power station, which involves too many areas, and the unknown risk in the implementation process

New energy power stations generally contain more than hundreds of grid-connected converters. If the impedance of each grid-connected converter is to be reshaped, cross-coupling and synchronous control between each other will cause unknown risks

[0007] 4) The existing method requires the grid-connected converter to have the function of impedance reshaping, which has high requirements for equipment manufacturers

Therefore, existing methods have certain difficulties in practical implementation.

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