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INSTALLATION - COMMISSIONING
Systems must be commissioned according to AS/NZS 5033. Commissioning tests are required to ensure
that the system complies with the aforementioned standard. Commissioning information is provided here as
a guide only and it is the installer’s responsibility to ensure that the requirements of AS/NZS 5033 are met. A
copy of the relevant commissioning documents must be provided to the owner and a copy kept by the
installer.
Before starting any of the tests below, ensure that:
The Solar Supply Main Switch at the AC switchboard is in the OFF position.
The Inverter AC Isolator at the inverter is in the OFF position (if installed).
The Inverter DC Isolator(s) at the inverter are in the OFF position.
The Rooftop DC Isolator(s) are in the OFF position.
Warning:
Dangerous DC voltages may be present during the following commissioning procedure.
Appropriate personal protective equipment should be used.
VERIFICATION OF MODULE AND RAIL EARTH RESISTANCE
This test is performed to ensure modules and rails are correctly earthed.
1.
Using a multimeter set on the ohms scale, measure between each module and the system earth wire.
Earth resistance must be 0.5 Ω or less.
2.
Using a multimeter set on the ohms scale, measure between each rail and the system earth wire. Earth
resistance must be 0.5 Ω or less.
STRING OPEN CIRCUIT VOLTAGE (V
OC
) TEST
This test is performed to ensure the wiring polarity and continuity of the PV array is correct. Measurements
should be made under stable irradiance conditions close to solar noon if possible. Where multiple strings are
installed, this test procedure must be repeated for each string.
The voltage measurement obtained should be the number of modules in the string multiplied by the V
oc
of
one module i.e. for a string with 9 X REC255PE modules: String V
oc
= 9 X 35.3 V DC ≈ 318 V DC.
1.
Ensure that the Inverter AC Isolator(s) are in the OFF position.
2.
Ensure that the Inverter DC Isolator(s) are in the OFF position.
3.
Ensure that the Rooftop DC Isolator(s) are in the OFF position.
4.
Using a multimeter set on the DC voltage scale, measure between the string positive and negative
terminals at the module side of the string Rooftop DC Isolator and compare the value obtained with the
table below.
5.
Repeat for each string.
Indicative String V
oc
@ NOCT*
Number of modules in string
4
5
6
7
8
9
10
11
12
13
14
HSL60P6-PB-1-250 modules
140 175 210 245 280 315 350 385 420 455
490
REC255PE modules
142 177 212 247 282 318 353 388 424 459
494
* Values measured at normal operating cell temperature (NOCT) defined as: irradiance of 800 W/m2,
Spectrum AM 1.5, wind speed 1 m/s and ambient temperature 20ºC. Variations from NOCT values will affect
actual Voc and should be allowed for.
The open-circuit voltage (V
oc
) of every string must be measured before switching on the inverter and must be
within 5% of the calculated value. If readings are outside the calculated value by more than ±5%, then
connections must be verified for polarity, continuity and possible faults and repaired where necessary. Once
verification has been satisfactorily completed, strings may then be connected to the inverter.
