Device and method for detecting photovoltaic module-to-ground insulativity and photovoltaic grid-connected power generation system

Abstract

The invention discloses a device and method for detecting photovoltaic module-to-ground insulativity and a photovoltaic grid-connected power generation system. The detection device comprises a first detection resistor, a second detection resistor, a third detection resistor, a first switch device and a second switch device, wherein the first detection resistor is connected with an anode-to-ground resistor of a photovoltaic module in parallel; the second detection resistor is connected with a cathode-to-ground resistor of the photovoltaic module in parallel; the third detection resistor is connected with the first switch device in series; a series branch where the third detection resistor and the first switch device are located is connected with the second detection resistor in parallel, or the series branch is connected with the first detection resistor in parallel; the second switch device is used for controlling the conducting state between the common node of the first detection resistor and the second detection resistor and the ground wire of a photovoltaic inverter and is used for controlling the conducting state between the common node and the null line of a power supplying power grid. By the adoption of the technical scheme, reliability of detection on the photovoltaic module-to-ground insulativity is guaranteed.

Description

technical field [0001] The present invention relates to the technical field of photovoltaic power supply, and more particularly, to a device and method for detecting the insulation of photovoltaic components to the ground and a photovoltaic grid-connected power generation system. Background technique [0002] The photovoltaic grid-connected power generation system converts the direct current generated by the solar cell into alternating current of the same frequency and phase as the voltage of the power supply grid. Among them, the photovoltaic inverter is an important component of the photovoltaic grid-connected power generation system. [0003] In order to ensure the safety and stability of the photovoltaic grid-connected power generation system, it is necessary to test the ground insulation resistance of photovoltaic modules before grid connection. [0004] However, the existing photovoltaic module-to-ground insulation resistance detection circuits all detect the ground-t...

AI Technical Summary

Problems solved by technology

As long as one of the ground wire of the photovoltaic inverter and the neutral wire of the power supply grid is grounded invalid, the existing detection circuit cannot detect that the grounding abnormality is caused by an abnormal grounding of the ground wire of the photovoltaic inverter or the neutral wire of the power grid. It is also caused by the abnormal insulation of the photovoltaic module to the ground. At this time, the detection result of the insulation of the photovoltaic module to the ground will be unreliable

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