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1. Introduction
The PVI 14TL and PVI 20TL are commercial, dual MPPT, three-phase grid-tied transformerless PV
inverters designed to be interconnected to the electric utility grid.
The inverter is listed for use
with ungrounded (floating) PV arrays only. By following this manual the inverter can be installed
and operated safely. This installation guide is used as a reference for commissioning and as a
guideline on how to use the inverter most effectively.
Feeding power back to the grid involves conversion of the DC voltage from the PV array to grid
compatible AC voltage by inverting DC to AC. This unit feeds power into a standard, three-phase
commercial, industrial, institutional or electrical utility facility’s electrical system which is
connected to the electrical grid.
If the PV system and inverter are providing the same amount of electrical power that the facility
is using, then no power is taken from or fed into the utility grid. If the facility is using more power
than the PV system is providing, then the utility grid provides the balance of power. If the facility
is using less power than the PV system is generating, then the excess is fed into the utility grid.
Be sure to follow local regulations regarding net metering and interconnection in your local area.
Note that some utilities need to change their revenue kWh meter for proper net metering
measurement and billing.
Figure 1.1 – Grid-Tied Inverter Application
Photovoltaic
Array
PVI 14TL
PVI 20TL
Inverter
Electrical
Grid