Insulation monitoring method and device and new energy power generation system

Abstract

The invention discloses an insulation monitoring method and device and a new energy power generation system, generally, an inverter is shut down at night and grid-connected in the daytime, the switching process of anti-PID equipment and insulation monitoring equipment is divided into two periods of inverter shut-down and inverter grid-connected for insulation monitoring, and insulation monitoring is carried out all day long while the PID effect is inhibited. Specifically, when it is monitored that the inverter is shut down, alternating current insulation monitoring is continuously carried out on the alternating current side, and when the monitored alternating current insulation resistance meets the preset normal alternating current resistance condition and the inverter works and meets the grid connection condition, direct current insulation monitoring is carried out before grid connection of the inverter. When the direct-current insulation resistance value meets a preset normal direct-current resistance value condition, the inverter is controlled to be connected to the grid, and alternating-current and direct-current insulation monitoring is stopped; and during the grid connection period of the inverter, controlling the anti-PID equipment and the alternating current insulation monitoring equipment to alternately execute.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation, and more particularly, to an insulation monitoring method, a device and a new energy power generation system. Background technique [0002] In the process of photovoltaic power generation, the inverter converts the photovoltaic energy into a sine wave current with the same frequency and phase as the grid, and feeds it into the grid. Due to the characteristics of photovoltaic panels, a PID (Potential Induced Degradation) effect will be generated on the photovoltaic panels during the photovoltaic energy conversion process. Therefore, it is necessary to suppress the PID effect. [0003] In the prior art, an anti-PID device is usually used to raise the voltage of the negative pole of the photovoltaic string relative to the ground, so as to suppress the PID effect of the photovoltaic panel. In the process of reverse PID operation, since the reverse PID device has a ground loop ...

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Problems solved by technology

In the process of anti-PID operation, since the anti-PID equipment has a ground loop to the ground, the insulation monitoring device (Insulation Monitoring Device, IMD for short) installed on the AC side cannot monitor the insulation resistance of the ground. Based on this, in the prior art Generally, the insulation monitoring equipment is only turned on at night

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