Real-time stability control device for new energy grid-connected systems

Abstract

The invention discloses a real-time stable control device suitable for new energy grid-connected systems. The device is installed between the new energy power station and the power system to be connected. The hardware part consists of series voltage injection, parallel current injection, power collection and The real-time controller and other circuit modules are composed, and the software part is composed of sweep frequency harmonic calculation, real-time impedance analysis, weak damping area discrimination, impedance correction calculation, oscillation signal extraction, compensation signal calculation and other modules. This device calculates the impedance of new energy power stations and power systems in real time through continuous frequency sweep harmonic signal injection, determines the weak damping area of ​​the system online, and corrects the impedance of the system in the full frequency band in real time through the injection of series compensation signals and parallel compensation signals , making the system always stable. The device can effectively prevent broadband oscillation when new energy is integrated into the power system, has good real-time performance, and does not need to change the control mode of the grid-connected converter in the 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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