Electromagnetic transient stability device of distributed power generation system and method

Abstract

The invention discloses an electromagnetic transient stability device of a distributed power generation system and a method. The electromagnetic transient stability device is connected into an alternating current bus of the distributed power generation system in parallel, and comprises a power unit, a filter unit, a detecting unit, a control unit and an impedance calculation unit, wherein the output end of the power unit is connected with the input end of the filter unit; the output end of the filter unit is connected into the alternating current bus of the system in parallel; the input end of the detecting unit is connected with the output end of the filter unit; the input end of the impedance calculation unit is connected with the output end of the detecting unit; the output end of the impedance calculation unit is connected with the input end of the control unit; and the output end of the control unit is connected with the control end of the power unit. The detecting unit samples output voltage and current signals of the electromagnetic transient stability device; the impedance calculation unit calculates the impedance of an external system according to the output voltage and current signals; the control unit resets the self impedance of the device according to the impedance, so that resonant vibration is damped; the grid-connected current waveform quality is improved; and the grid-connected stability is improved.

Description

technical field [0001] The invention belongs to the technical field of power generation systems, and in particular relates to an electromagnetic transient stabilization device and method for a distributed power generation system. Background technique [0002] For an ideal distributed power generation system, all parameters in the system are fixed. According to a reasonable design, the control system can have high stability, and there is no harmonic oscillation in the system. However, in the actual power grid, due to the influence of parameters such as transmission lines, the grid impedance cannot be ignored, and the power grid presents weak network characteristics. The interaction between the distributed power generation device (grid-connected inverter) and the grid will cause harmonic oscillation. Reduce the power quality and stability of distributed generation systems. In addition, the existing flexible AC transmission (FACTS) devices, such as active power filter (APF) an...

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Problems solved by technology

However, in the actual power grid, due to the influence of parameters such as transmission lines, the grid impedance cannot be ignored, and the power grid presents weak network characteristics. The interaction between the distributed power generation device (grid-connected inverter) and the grid will cause harmonic oscillation. Reduced Power Quality and Stability of Distributed Generation Systems

In addition, the existing flexible AC transmission (FACTS) devices, such as active power filter (APF) and unified power quality controller (UPQC), are mainly used to suppress supersynchronous resonance, but the suppression effect on subsynchronous resonance is not ideal ; At the same time, the FACTS device can only perform compensation design for a specific resonant frequency of the system when the impedance of the grid-connected inverter and the grid are known, which has poor flexibility and no autonomy

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