A low-voltage ride-through detection device for small grid-connected photovoltaic inverters

Abstract

The invention provides a low-voltage ride-through detection device for a small-scale grid-connected photovoltaic inverter. The other ends of the air-core reactors are respectively connected to the connected short-circuit breaker and the short-circuit switching switch, and the other end of the short-circuit switching switch is connected to the neutral line through the neutral point circuit breaker; the air-core reactor is simultaneously As a device for current limiting reactor and short circuit reactor. The device is low in cost and easy to operate. On the basis of realizing the integrated design, only the main circuit of the incoming and outgoing lines needs to be connected externally, the control operation is convenient, and the floor space and maintenance amount of the detection device are reduced.

Description

technical field [0001] The invention relates to a system in the field of photovoltaic power generation, in particular to a low-voltage ride-through detection device for a small grid-connected photovoltaic inverter. Background technique [0002] With the increasing proportion of photovoltaic power generation in electric energy, the impact of photovoltaic power generation system on the power grid can no longer be ignored. When the power grid fails and the voltage at the grid-connected point drops, once the photovoltaic power station is disconnected from the grid on a large scale, it may cause the collapse of the grid voltage and frequency, which will seriously affect the safe and stable operation of the grid. Therefore, large-scale photovoltaic power plants must have low-voltage ride-through capabilities. [0003] The national standard GB / T 19964-2012 "Technical Regulations for Connecting Photovoltaic Power Stations to Power Systems" promulgated in 2012 clearly stipulates that...

AI Technical Summary

Problems solved by technology

[0008] (1) Large-scale detection devices need to use multiple sets of reactors for series and parallel connection, which is costly and occupies a large area;

[0009] (2) Medium-voltage circuit breakers are used in large-scale detection devices to simulate voltage drops. The circuit breakers have a certain switching life and need to be replaced after a certain number of times, resulting in waste of equipment;

[0010] (3) The use of large-scale detection devices needs to consume a large amount of inductive reactive power, resulting in a certain degree of waste of electric energy;

[0011] (4) Part of the detection structure only needs to detect small inverters, which does not meet the grid capacity configuration for building large-scale detection devices;

[0012] (5) If a small detection device is designed according to the design concept of a large detection device, its own cost performance is too low, the integration is not good, and it is not easy to promote

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