Do PV inverters need AC side grounding?

When a PV plant is installed in the distribution feeder, the plant shall meet the IEEE 1547 standard and the interface requirements of the local utility company. Some utility companies require PV inverters to have AC side grounding in order to assure compatibility with their grounding scheme, generally referred to as effective grounding.

What is a grid-tied inverter-based PV plant?

In contrast, a grid-tied inverter-based PV plant is modeled as a current source whereby the plant’s terminal voltage is dependent on the feeder. A PV plant is comprised of inverters using power semiconductor switches and microprocessors.

How does a PV inverter protect against a grid fault?

Protective relay functions are built directly into the PV inverter. A PV inverter does not have any mechanical inertia. During a grid fault condition, the inverter short circuit current is equivalent to its rated current and the inverter disables its operation within one or a few cycles.

Does a grid tied PV inverter have a transformer?

Many grid tied PV inverters have an internal transformer. If the transformer is wye-delta configured with the wye on the grid side, the neutral terminal can be used for effective grounding as shown in Figure 3 a). In most of the cases, the grid voltages are well balanced and the distribution loads contain limited harmonic current.

Why do I need a grounding Bank for a PV plant?

As the device is connected external to the inverters, it allows for the inverters to be connected without neutral. If there are multiple inverters used in a PV plant, only one grounding bank is required at the PCC to achieve effective grounding for the whole plant.

How does a PV plant work?

A PV plant is comprised of inverters using power semiconductor switches and microprocessors. Abnormal operation can be detected instantaneously by the control processor and the plant can be protected with response times that are much faster than those of conventional generators. Protective relay functions are built directly into the PV inverter.