Xantrex Technology PV-30208 Section Safety Isolation Procedure, Anti Island Protection

SECTION 2

SAFETY

ISOLATION PROCEDURE

Anti Island Protection

A digital phase-shift-loop (PSL) circuit is implemented in the DSP inverter controller to prevent “Islanding” of the PV-30208.

The DSP continuously makes minor adjustments to the power factor phase angle above and below unity. In the event of a utility outage, these adjustments destabilize the feedback between the inverter and the remaining load, resulting in an over/under frequency or voltage condition. The PV-30208 then performs an orderly shutdown. The fault condition will remain until the utility voltage and frequency have returned to normal for 5 minutes.

This method has been extensively tested and proven to exceed the requirements of UL1741.

The following procedure should be followed to de-energize the PV-30208 for maintenance:

WARNING

The terminals of the PV input may be energized if the arrays are energized. In addition, allow 5 minutes for all capacitors within the enclosure to discharge after disconnecting the PV-30208 from AC and DC sources.

1.Turn the on/off switch to the off position.

2.Open the PV array disconnect switch (if present).

3.Open the AC interface disconnect (if present).

4.Open the isolation transformer circuit breaker.

5.Install lockout devices on the isolation transformer circuit breaker and PV disconnect switch (if present).

DOCUMENT: 151315PV-30208 Photovoltaic Inverter2-2

Operation and Maintenance Manual

Copyright 2003, Xantrex Technology Inc.