Inverter voltage resistance measurement

How do you measure the insulation resistance of a PV inverter?

One method is to measure the insulation resistance of each panel with respect to ground. This indirectly also measures the leakage current. The measurement is usually done before the turning on of the PV inverter or at least once or twice per day. For a 1000 Vdc system, normal practice requires insulation resistance to be more than 1 MΩ.

When should I measure the isolation resistance of my inverter?

The isolation resistance is measured during every restart of the inverter and also during operation. In case your inverter displays an earth fault (E34 Insulation), be aware that an isolation error is a severe risk which can result in fire or electric shock. To mitigate this risk, it is necessary to measure the isolation resistance.

Why is inverter testing necessary?

Inverter testing is necessary in order to check for malfunctions of the inverter. This section introduces insulation resistance testing and voltage/current measurement, two tasks that are sometimes used in inverter testing. Insulation resistance testing is used to check for degradation in wire insulation.

What is a high voltage system in a PV inverter?

High voltage system in PV inverters operation requires a safe insulation resistance between the PV panel to ground. A poor insulation resistance less than 1 MΩ leads to a high leakage current (about 1 mA), which not only will damages the system but also injure the user.