Method for improving active support control fault ride-through capability based on virtual impedance FCL

Abstract

The invention belongs to the technical field of methods for improving the fault ride-through capability of renewable energy stations, and particularly relates to a method for improving the active support control fault ride-through capability based on virtual impedance FCL. The method comprises the following steps of formulating an active support control strategy of a renewable energy field station; formulating an emergency voltage control strategy of the renewable energy field station; and analyzing the low-voltage ride-through capability of the renewable energy field station in a three-phasesymmetric fault state. According to the invention, the grid-connected stability of the renewable energy field station can be improved, the severe influence on a phase locking result due to the use ofa PLL (phase locked loop) in a three-phase symmetric fault state of the system is avoided, so that the renewable energy field station has the characteristic of flexibility and controllability, and theeffect of low-voltage ride through of the renewable energy field station under the three-phase symmetric faults of different degrees is achieved. When a fault occurs, the grid-connected operation ofthe renewable energy field station is not interrupted, and the complex synchronous operation process of reconnecting to the system is avoided. The method does not need the extra hardware equipment, and has the characteristics of flexibility and low cost.

Description

technical field [0001] The invention belongs to the technical field of a method for improving the fault ride-through capability of a renewable energy station, and in particular relates to a method for improving the fault ride-through capability of active support control based on a virtual impedance FCL. Background technique [0002] According to the medium and long-term development plan of renewable energy, the installed capacity of renewable energy will continue to grow rapidly year by year in the future, while the load growth will be stable, and the system will face greater pressure to accommodate renewable energy. A large number of wind turbines, photovoltaic and energy storage devices are integrated into the system, making it difficult to solve the problem of system voltage stability. In a high-proportion renewable energy system, due to the lack of support and reactive power compensation capabilities of the traditional synchronous generator automatic excitation system fo...

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Problems solved by technology

[0012]Aiming at the problems existing in the above-mentioned prior art, the present invention proposes a method based on virtual impedance FCL to improve the ability of active support control fault ride-through, the purpose of which is to solve In the prior art, under the active support control strategy, the renewable energy station responds to the problem of insufficient low-voltage ride-through capability under the three-phase symmetrical fault state of the system

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