How to measure PV panel impedance?

1. Turn off device and Un-plug PV contactor

2. Turn multi-meter to DC voltage

3. Use probe+ to touch PV+ and probe- to earth

4. Record data

5. Use probe+ to touch PV- and probe- to earth

6. Record data

7. Usually, if both PV+/- voltage are in low it is normal. Only PV+/PV- voltage difference is larger than 30V means PV impedance value abnormal