Marshall Islands March 31-April 11, 2008
８・５ －Field Inspection Items
8.5.1 Visual inspection and verification test of structure and quantity
（1）Photovoltaic module
（2）Support structure for photovoltaic module
（3）Power conditioner
（4）Display system
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（5）Junction box, Interconnection switchboard, MCB
8.5.2 Equipment installation and wiring/connection inspection
（1）Equipment installation inspection
（2）Wiring/connection verification test
8.5.3 Insulation resistance test
（1）Wiring between photovoltaic modules
（2）Wiring between various equipment
8.5.4 Open-circuit voltage test/earth resistance test
（1）Open-circuit voltage of photovoltaic module
（2) Earth resistance when systems are interconnected
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Marshall Islands March 31-April 11, 2008
8.5.1 －Visual inspection and verification test of structure
and quantity
（1） Photovoltaic module visual inspection and power output test
Item
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Appearance
Inspection details
Means of inspection
・Check if there is any
damage, cracking or
deformation in the
photovoltaic module
appearance.
Visual inspection
・Confirm that photovoltaic
modules are appropriately
arranged.
Power
output
Result
Consistent with
Tech. Spec.
drawings
・Check against
manufacturers’ shop
inspection records on
behalf of conducting field
output tests.
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8.5.1 －Visual inspection and verification test of structure
and quantity
（2）Visual inspection of Support structure for photovoltaic module array
Item
Appearance
Installation
Wiring
Inspection details
Means of inspection
There is no deformation or strain.
Visual inspection
There is no peeling of galvanized steel
welded to support structure.
Visual inspection
The support structure is appropriately
arranged.
Consistent with Tech.
Spec. drawings
There is no loosening in screws, bolts and
fixtures.
Visual inspection
Bolt tightening is appropriately conducted.
Visual inspection
There is no loosening in the connections
between photovoltaic modules.
No loosening is
confirmed by touching
and visually.
Exposed cables behind the photovoltaic
module are wired in order.
Visual inspection
Cables are supported by fixing devices.
Visual inspection
Earth cables are connected to the array
support structure.
Visual inspection
Result
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8.5.1 －Visual inspection and verification test of structure
and quantity
（3） Power conditioner
Visual inspection
Item
Inspection details
Means of inspection
Appearance
There is neither peeling of surface coating
nor deformation.
Visual inspection
Installation
There is no loosening in screws, bolts and
fixtures.
Visual inspection
P/N（+/-） are correctly connected at the
power conditioner input.
Visual inspection,
tester
R/S/T are correctly connected at the threephase output.
Visual inspection,
tester
Low voltage cable +/- are correctly
connected at its input/output.
Visual inspection,
tester
Earth cables are connected.
Visual inspection
Cables are connected in order.
Visual inspection
The panel internal is clean.
Visual inspection
Wiring
Result
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Marshall Islands March 31-April 11, 2008
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8.5.1 －Visual inspection and verification test of structure
and quantity
（3） Power conditioner
Performance test
Item
Inspection details
Performance
Result
Remarks
Model/type
Check the type of power conditioner
against Tech. Spec.
Acceptable
Protective
relay test
(at shop)
Check against shop inspection
records on behalf of field relay tests.
Check against shop inspection records.
Islanding
phenomen
on
detection
MCCB（ELCB） is turned off and
operation is shutdown in an instance.
Acceptable
20
seconds
standby
after power
restoration
Performan
ce test
The power conditioner automatically
starts 20 seconds after power
restoration.
2
0
Restart on
S.
Acceptable
The time to
restoration
shall be
consistent with
Tech. Spec.
Regarding output inspection/test of relays, check against manufacturers’ shop
inspection records on behalf of conducting field inspection/test.
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8.5.1 －Visual inspection and verification test of structure
and quantity
（4）Display system
Visual inspection
Item
Inspection details
Means of inspection
Appearance
There is neither peeling of surface coating nor deformation.
Visual inspection
Installation
There is no loosening in screws, bolts and fixtures.
Visual inspection
Nameplate
There is no defect to or peeling of nameplate.
Visual inspection
Wiring
AC200V control power cables are correctly wired.
Visual inspection, tester
Low voltage cables are correctly wired and there is
conduction.
Visual inspection, tester
Cables are wired in order.
Visual inspection
The panel internal is clean.
Visual inspection
Result
LED verification test
Item
Verification
of quantity
Inspection details
The generated electricity is consistent with the total of the
numerical values shown in the power conditioner LCD.
Means of inspection
Result
Visual inspection
＊Input signals from the secondary cable in the transducer inside the interconnection switchboard to verify
the indicated values on the LED screen.
＊Visually check the numerical values indicated by power conditioner panel LCD or data collection system
monitor to verify there is no error in the generated electricity of photovoltaic module and inverter output.
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8.5.1 －Visual inspection and verification test of structure
and quantity
（5）
Junction box, interconnection switchboard and MCB
Visual inspection of junction box-1
Item
Inspection details
Means of
inspection
Appearance
There is neither peeling of surface coating nor
deformation.
Visual inspection
Installation
There is no loosening in screws, bolts and fixtures.
Visual inspection
P/N（+/-） are correctly connected at the junction
box input.
Visual inspection,
tester
P/N（+/-） are correctly connected at the MCCB
output.
Visual inspection,
tester
Earth cables are connected.
Visual inspection
Cables are wired in order.
Visual inspection
The panel internal is clean.
Visual inspection
Wiring
Result
7
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
8.5.1 －Visual inspection and verification test of structure
and quantity
（5）
Junction box, interconnection switchboard and MCB
Visual inspection of interconnection switchboard
Item
Inspection details
Means of
inspection
Appearance
There is neither peeling of surface coating nor
deformation.
Visual inspection
Installation
There is no loosening in screws, bolts and fixtures.
Visual inspection
U/V/W are correctly connected at the inverter input.
Visual inspection,
tester
U/V/W are correctly connected at the main MCCB
output.
Visual inspection,
tester
Earth cables are connected.
Visual inspection
Cables are wired in order.
Visual inspection
The panel internal is clean.
Visual inspection
U/V/W phase indicator shows the positive phase at
the inverter input
Visual inspection,
phase indicator
Wiring
Result
8
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
8.5.1 －Visual inspection and verification test of structure
and quantity
(5) Junction box, interconnection switchboard and MCB
Visual inspection of MCB
Item
Inspection details
Means of
inspection
Appearance
There is neither peeling of surface coating nor
deformation.
Visual inspection
Installation
There is no loosening in screws, bolts and fixtures.
Visual inspection
U/V/W are correctly connected at the main MCCB
input.
Visual inspection,
tester
U/V/W are correctly connected at the main MCCB
output.
Visual inspection,
tester
Earth cables are connected.
Visual inspection
Cables are wired in order.
Visual inspection
The panel internal is clean.
Visual inspection
U/V/W phase indicator shows the positive phase at
main MCCB output.
Visual inspection,
phase indicator
wiring
Result
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8.5.2 －Equipment installation and wiring/connection inspection
（1）, （2） Insulation resistance measurement of cable between junction box and inverter panel
Insulation resistance measurement of cable between inverter and interconnection witchboard
Insulation resistance measurement of cables between interconnection switchboard, MCB and
existing transducers
［Test procedure］
Measure the insulation resistance of （+，－） polarities and （R，S,T） phases of each cable to ensure
that there is no insulation failure.
Measure the insulation resistance between each cable and the ground (according to the rules for
internal cables).
［Acceptance criteria］
Measured voltage＞600V： Acceptable if measurement using 1000V megger shows 0.4MΩ or igher .
Measured voltage＞300V： Acceptable if measurement using 500V megger shows 0.4MΩ or higher
Measured voltage＞150V： Acceptable if measurement using 500V megger shows 0.2MΩ or higher.
Measured voltage＞150V： Acceptable if measurement using 500V megger shows 0.1MΩ or higher.
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Marshall Islands March 31-April 11, 2008
8.5.2 -Equipment installation and wiring/connection inspection
Measurement of cable insulation resistance
Item
Insulation resistance （M ）
Junction box-1
～Inverter-1
P（＋）
100MΩ or higher
N（－）
100MΩ or higher
Junction box-2
～Inverter-2
P（＋）
100MΩ or higher
N（－）
100MΩ or higher
Junction box-3
～Inverter-3
P（＋）
100MΩ or higher
N（－）
100MΩ or higher
Cable type
Result
CV10sq-4C
Earth cable 1C, spare cable 1C
>600V
CV10sq-4C
Earth cable 1C, spare cable IC
>600V
CV10sq-4C
Earth cable 1C, spare cable IC
>600V
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Inverter-1～Interconnection switchboard
R（red）
100MΩ or higher
S（black）
100MΩ or higher
T（blue）
100MΩ or higher
N（white）
100MΩ or higher
>300V
CV14sq-4C
Interconnection switchboard～MCB
R（red）
100MΩ or higher
S（black）
100MΩ or higher
T（blue）
100MΩ or higher
N（white）
100MΩ or higher
CV100sq-4C
>300V
MCB～Existing transducer-9
R（red）
100MΩ or higher
S（black）
100MΩ or higher
T（blue）
100MΩ or higher
N（white）
100MΩ or higher
>300V
CV100sq-4C
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Marshall Islands March 31-April 11, 2008
8.5.3 －Equipment installation and wiring/connection inspection
（1）、（2） Insulation resistance measurement of cables between photovoltaic modules
［Test procedure］
Measure the insulation resistance of （+，－） polarities and （R, S, T) phases of each cable for one string of
photovoltaic module array to verify that there is no insulation failure.
Measure the insulation resistance between each cable and the ground (*The insulation resistance of the
cable including the photovoltaic module will be measured).
［Acceptance criteria］
Open-circuit voltage≧300V： Acceptable if measurement using 1000V megger shows 0.4MΩ or higher .
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Measurement of cable insulation resistance
Module No.
Insulation resistance
（M ）
Cable used
Result
Manufacturer’s standard type （4sq-5C）
1C earth cable, spare cable 2C
Acceptable
Manufacturer’s standard type （4sq-5C）
1C earth cable, spare cable 2C
Acceptable
Manufacturer’s standard type （4sq-5C）
1C earth cable, spare cable 2C
Acceptable
Manufacturer’s standard type （4sq-5C）
1C earth cable, spare cable 2C
Acceptable
Manufacturer’s standard type （4sq-5C）
1C earth cable, spare cable 2C
Acceptable
Junction box-1
PV1-1
+
65MΩ or higher
PV1-1
-
100MΩ or higher
PV1-2
+
100MΩ or higher
PV1-2
-
200MΩ or higher
PV1-3
+
150MΩ or higher
PV1-3
-
200MΩ or higher
PV1-4
+
100MΩ or higher
PV1-4
-
200MΩ or higher
PV1-5
+
50MΩ or higher
PV1-5
-
90MΩ or higher
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
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8.5.4 －Open-circuit voltage test/earth resistance test
（1）DC Open-circuit voltage of cables between photovoltaic modules
The crystalline photovoltaic power generation system consists of 270 panels of 167 W
module.
Eighteen modules （167W） in series ×fifteen modules in parallel constitute a photovoltaic
power generation system.
The open-circuit voltage of one module is about 43.1V（at the highest）with an error of
±10%.
Accordingly, the nominal voltage of one module accounts for 43.1V×0.9～1.1＝
38.79～47.41V.
The maximum open-circuit voltage of one circuit consisting of 18 modules will be:
38.8V×18 modules＝698.22V （lower limit）
47.4V×18 modules＝853.38V （upper limit）
［Test procedure］
・Measure the open-circuit voltage of one each string of photovoltaic module array to
confirm the polarity of each circuit.
・ Measure the open-circuit voltage of one each string of photovoltaic module array to check
if the number of modules in series is correct or not.
＜If the measured voltage is out of the acceptance criteria, the modules in series might be
incorrectly connected.＞
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Marshall Islands March 31-April 11, 2008
8.5.4 －Open-circuit voltage test/earth resistance test
（1）DC Open-circuit voltage of cables between photovoltaic modules
［Test conditions］
Tests shall be conducted during daytime hours on a sunny day.
（Solar radiation shall be 0.1kW/m2 or higher.）
［Acceptance criteria］
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Measure the open-circuit voltage of one each string of module array to confirm that it meets
the following criteria.
Measurement at junction box
Module train No.
Junction box-1
Polarity （+，-）
Acceptance criteria
Open-circuit voltage (Voc)
698V～853V
Junction box-1
PV1-1
O.K
744.0V
Acceptable
PV1-2
O.K
740.0V
Acceptable
PV1-3
O.K
737.0V
Acceptable
PV1-4
O.K
735.0V
Acceptable
PV1-5
O.K
734.0V
Acceptable
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8.5.4 －Open-circuit voltage test/earth resistance test
（2） Earth resistance measurement
［Test procedure］
Measure the earth resistance.
［Acceptance criteria］
Earth resistance of 100 or less is acceptable.
Earth resistance
Item
Measured value
Result
Interconnection point
1.6Ω
Acceptable
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