Adjustable impedance distributed photovoltaic power generation cluster resonance suppression system and suppression method

Abstract

The invention discloses an adjustable impedance type distributed photovoltaic power generation cluster resonance suppression system and a suppression method. The system comprises a central control unit, a resonance suppression unit and a reactive power regulation unit, wherein the central control unit, the resonance suppression unit, the reactive power regulation unit and a distributed photovoltaic power generation cluster are connected to a common connecting point in parallel through system buses, and the central control unit, the resonance suppression unit and the reactive power regulation unit are connected into a power distribution network together with the distributed photovoltaic power generation cluster through a power distribution network line equivalent inductor Lg. The signal output end of the reactive power regulation unit is connected with the signal input end of the central control unit, the signal input end of the reactive power regulation unit is connected with the signal output end of the central control unit, and the signal input end of the resonance suppression unit is connected with the signal output end of the central control unit. The method includes the steps that when the central control unit detects that a system generates resonance, reactor sets in the resonance suppression unit are cyclically switched in sequence from the middle stage till the parallel resonance of the system is suppressed. By means of the adjustable impedance type distributed photovoltaic power generation cluster resonance suppression system and the suppression method, the resonance of the distributed photovoltaic power generation cluster system is effectively suppressed on the basis that an original photovoltaic inverter control algorithm is not changed.

Description

technical field [0001] The invention relates to a method for suppressing the resonance of a photovoltaic power generation cluster. In particular, it relates to an adjustable impedance distributed photovoltaic power generation cluster resonance suppression system and suppression method. Background technique [0002] In recent years, my country's distributed photovoltaic has shown the characteristics of continuous development and cluster grid connection. The fluctuation, intermittent and random characteristics of photovoltaic power generation make the output of photovoltaic cluster system contain voltage and current with rich harmonic spectrum. At the same time, there are a large number of LCL filters in the distributed photovoltaic power generation cluster system, which constitute a complex high-order electrical network with the impedance of the distribution network, so that there are a large number of inherent resonance points in the photovoltaic cluster system. Therefore,...

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Problems solved by technology

At present, the active resonance suppression device is limited by the capacity and voltage level, the switching frequency cannot be increased, and the suppression effect on high-order harmonic resonance is not ideal, while the passive resonance suppression device will cause great energy loss, and It has a great adverse effect on the grid-connected point voltage

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