Distributed photovoltaic power generation system grid-connected safety equipment and control method

Abstract

The invention discloses a grid connection safety device and control method for a distributed photovoltaic power generation system. The grid connection safety device comprises a distributed photovoltaic power generating system, a three-phase power grid in grid connection with the distributed photovoltaic power generating system and a grid connection switch controlling connection and disconnection of the power grid. The grid connection safety device further comprises a signal acquisition module, a main controller, a relay module and a delayed tripping module, wherein the signal acquisition module receives a voltage signal and a current signal of the three-phase power grid, the main controller judges whether the voltage signal and the current signal are safe and gives undervoltage and overcurrent protecting commands, the relay module receives the commands of the main controller and is connected to a direct current power supply rectified by the three-phase power grid, and the delayed tripping module receives the commands of the main controller and controls the grid connection switch. The grid connection safety device for the distributed photovoltaic power generation system reduces power grid cost and has the complete overvoltage, undervoltage and overcurrent protecting functions. Technicians can set overvoltage, undervoltage and overcurrent protecting thresholds and protecting delay time in real time in a stepless mode according to the site situation.

Description

technical field [0001] The invention belongs to the technical field of distributed photovoltaic power generation, in particular to a grid-connected safety device and a control method for a distributed photovoltaic power generation system. Background technique [0002] In recent years, distributed photovoltaic power generation has been widely used in industrial plants, public buildings and residential roofs due to its advantages of small capacity, low voltage level, close to the load, and little impact on the power grid. As an important application method of solar power generation, distributed photovoltaic power generation can make full use of the characteristics of the widespread existence of solar energy and avoid the site constraints of centralized construction. Especially in the face of the reality of densely populated middle and eastern my country, its large-scale application prospects are extremely broad. [0003] In order to support the development of distributed photo...

AI Technical Summary

Problems solved by technology

Distributed photovoltaic grid-connected access locations are diverse and design schemes are diverse, which makes the selection of grid-connected switches and measurement, control and protection devices very complicated.

The performance of the protection device exceeds the project requirements, and there is a phenomenon of functional redundancy, which leads to an increase in equipment configuration costs and seriously affects the customer's return on investment

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