Anti-countercurrent grid-connected photovoltaic power generation system

Abstract

An anti-countercurrent grid-connected photovoltaic power generation system (1) comprises at least one inverter (11) and an acquisition and control unit (12) connected with each inverter. The acquisition and control unit determines whether a countercurrent phenomenon occurs according to power output to a load (3) by a public power grid (2) and power output to the load by the grid-connected photovoltaic power generation system, which are acquired in real time. When it is determined that a countercurrent phenomenon occurs, the acquisition and control unit controls operation of the inverter, and reduces the power output to the load by the anti-countercurrent grid-connected photovoltaic power generation system until the acquisition and control unit determines that no trend toward a countercurrent phenomenon exists. The system can predict occurrence of a countercurrent phenomenon in advance, and avoid occurrence of the countercurrent phenomenon.

Description

technical field [0001] The invention relates to photovoltaic power grid-connected technology, in particular to a photovoltaic grid-connected power generation system for preventing backflow. Background technique [0002] In order to realize the sustainable development of energy and environment, all countries in the world regard solar photovoltaic power generation as the development focus of new energy and renewable energy. At present, photovoltaic power generation grid-connected systems can be divided into two types: reversible flow and non-reverse flow photovoltaic grid-connected power generation systems. The irreversible flow system means that the power generated by the photovoltaic grid-connected system is always less than or equal to the power consumption of the load. When the power is insufficient, it is powered by the grid, that is, the photovoltaic grid-connected power generation system and the grid form a dual power supply to supply power to the load. Even if the sur...

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Problems solved by technology

[0004] In the prior art, the direction and size of the voltage, current and power of the photovoltaic grid-connected power generation system are collected and detected by adding acquisition equipment, and the reverse power relay is used to analyze these data to determine whether there is a reverse flow phenomenon, and then output a control signal to control the grid connection The power is adjusted on the AC side to realize reverse current protection. This protection method can only send out a control signal for reverse current protection when a reverse current phenomenon occurs, and cannot predict the occurrence of reverse current phenomenon in advance, so that the occurrence of reverse current phenomenon cannot be completely avoided.

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