Xantrex Technology PV-225208 Section Safety, Isolation Procedure, Anti Island Protection

SECTION 2

SAFETY

Over/Under Voltage and Frequency

The over/under frequency and voltage detection setpoints have been chosen to be in compliance with IEEE-929 and UL1741.

Fault Condition	Voltage Range	Trip Time
(% of Nominal)
VAC < 50%	VAC < 104	6 Cycles
50% < VAC < 88%	104 < VAC < 183	2 Seconds
88% < VAC < 110%	183 < VAC < 228	Normal Operation
110% < VAC < 137%	228 < VAC < 285	2 Seconds
137% < VAC	285 < VAC	2 Cycles
f < rated -0.7	f < 59.3	6 Cycles
f > rated +0.5	f > 60.5	6 Cycles

Anti Island Protection

A digital phase-shift-loop (PSL) circuit is implemented in the DSP inverter controller to prevent “Islanding” of the PV-225208.

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-225208 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 UL 1741.

ISOLATION PROCEDURE

The following procedure should be followed to de-energize the PV-225208 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 main enclosure to discharge after disconnecting the PV-225208 fromAC and DC sources.

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

2.Open the DC interface (PV array) disconnect switch.

3.Open the AC interface disconnect switch.

4.Open the isolation transformer circuit breaker.

5.Install lockout devices on the isolation transformer circuit breaker and PV disconnect switch.

DOCUMENT: 151811	PV-225208 Photovoltaic Inverter	2-2
	Operation and Maintenance Manual

Copyright 2003, Xantrex Technology Inc.