Checking the ground connection of photovoltaic inverter strings

Can a PV inverter detect a ground fault?

Ground-fault detection and interruption typically occur within the PV inverter, alerting the site owner to the fault’s presence. Locating the fault, however, can be challenging. This article will overview the tools and tests technicians can use to track down a ground fault in a PV array.

How to check a PV system for ground faults?

The exact procedure is described in the following sections. Check the PV system for ground faults by measuring the voltage. If the voltage measurement was not successful, check the PV system via insulation resistance measurement for ground faults. Proceed as follows to check each string in the PV system for ground faults.

Can a PV inverter be touched?

Touch the cables of the PV array on the insulation only. Do not touch any parts of the substructure or frame of the PV array. Do not connect PV strings with ground faults to the inverter. Ensure that no voltage is present and wait five minutes before touching any parts of the PV system or the product.

What happens if you leave a ground fault in a solar PV string?

If left undetected, ground faults can lead to inverter shutdowns, loss of system yield, or even fire. In this article, we’ll show you how to locate a ground fault in a solar PV string using only a multimixer, a basic understanding of voltage behaviour, and a method proven in real-world installations.

How do you know if an inverter has a ground fault?

Measure the remaining strings in the same manner. If the insulation resistance of a string deviates considerably from the theoretically calculated value, there is a ground fault present in that string. Reconnect to the inverter only those strings from which the ground fault has been eliminated. Reconnect all other strings to the inverter.

Can a ground fault energize a PV system?

While the ground fault is active, it can energize the bonded metallic components that comprise the PV system. The risk of severe shock from direct contact with conductive components increases for high-voltage DC systems such as utility-scale PV arrays, which operate at 1,500 Vdc.