In non-isolated PV grid-connected inverter design, there is a parasitic capacitance between the system and the ground. When the loop impedance is small, the loop among the photovoltaic system, the grid and the parasitic capacitance is formed.                                 

The parasitic capacitance produces a common mode current, and the current value (50/60 Hz) depends on the surface of the solar panel under climatic conditions. Touch the PV plate may cause leakage, which may also result electromagnetic interference, gate distortion, and other losses in the system. Therefore, the leakage current must be detected for safe control of the system.

open loop & closed loop current sensor	primary current range	maxmium current range	supply voltage	accuracy @25℃	installation method	image
SFG	0.3…1.5A	2*IPN	+5V	1.0%	PCB