© fronius 01/2006 fronius gfdi the following slides explain the ground fault detection and...
TRANSCRIPT
© Fronius 01/2006FRONIUS GFDI
The following slides explain the Ground Fault Detection and Interruption (GFDI) system in a FRONIUS IG inverter.
Please note that each slide is provided with sound. Please switch on your loudspeakers and press the keys at the bottom of each slide to proceed.
© Fronius 01/2006FRONIUS GFDI
FRONIUS Ground Fault Detection and Interruption
Installation instructions
Troubleshooting
What is a ground fault?
Contact FRONIUS tech support
© Fronius 01/2006FRONIUS GFDI
What is a ground fault?
NEC definition: An unintentional, electrically conducting connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth.
L1
L2=~
GND
Main page Installation instructions
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© Fronius 01/2006FRONIUS GFDI
Installation instructions
Connect PV/DC module frame ground to (5) and AC ground to (1).
Do not connect ground to the DC negative at any point This is already done inside the FRONIUS IG.
!!! Connecting the ground to DC negative prior to the inverter will circumvent the GFDI protection system and the inverter will indicate a ground fault. !!!
Ground fault troubleshootingMain page
© Fronius 01/2006FRONIUS GFDI
AC/DC ground terminal
Previous page
=~
GNDA
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L1
L2
GFDI fuse
Main page
© Fronius 01/2006FRONIUS GFDI
Ground fault troubleshootingGround fault detection system operation:
DC negative is grounded through the 1 A GFDI fuse.
=~
GND
AA
When the ground fault current exceeds 1 A, the ground fault fuse opens and the inverter shuts down with STATE Code: 434
434 troubleshooting
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L1
L2
Main page
© Fronius 01/2006FRONIUS GFDI
STATE 434 troubleshooting
Ground fault LED ON Ground fault LED OFF
Main page
© Fronius 01/2006FRONIUS GFDI
STATE 434: Ground fault LED ONSTATE 434 with LED ON indicates that there is a ground fault on the
PV module (DC) side of the system.
Follow steps below to locate the fault: Check the 1A GFDI fuse.
If the fuse is not blown, the ground fault current is less than 1A. Vice versa if the fuse is blown. Do not replace the fuse without
following the steps below! In both cases, remove the GFDI fuse from the fuse holder and using a
multi-meter, measure the following DC voltages: Between DC Positive terminal and Ground terminal V1.
Between DC Negative terminal and Ground terminal V2.
Continue…Main page
© Fronius 01/2006FRONIUS GFDI
State 434: Ground fault LED ON (continued)From the previous page, if V1 is approximately equal to V2 (±5%):
The ground fault could be a temporary fault caused by expansion/contraction due to temperature or other variations.
If the system does not recover and the problem persists (STATE 434 & V1 = V2), please contact FRONIUS tech support:
Continue…
V1 V2
If V1 is not equal to V2, then there is a ground fault in the system.
Continue to next page…
Previous page
© Fronius 01/2006FRONIUS GFDI
State 434: Ground fault LED ON (continued)
Continue…
Consider the PV system shown:
3 strings of 4 modules each
connected to a FRONIUS IG.
Under normal conditions: Voc = 400 V V1 = 400 V V2 = 0 V
When the GFDI fuse is removed,
the voltages should divide
approximately equally:
V1 = V2 = Voc/2
Previous page
© Fronius 01/2006FRONIUS GFDI
State 434: Ground fault LED ON (continued)
Continue…
1. First, remove the GFDI fuse. (For a string inverter system with a common negative bus, remove all the GFDI fuses.)
2. Connect only one string to the inverter and measure V1 and V2.
3. Again, when there is no fault in the string V1 = V2 = Voc/2.
4. Repeat steps 2,& 3 for each string.Since there is no fault on strings 1 and 2, Voc is split equally between V1 and V2.
Assume there is a ground fault on the rightmost string. Follow the steps below to locate the fault:
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© Fronius 01/2006FRONIUS GFDI
State 434: Ground fault LED ON (continued)
5. When there is a fault in the string, Voc does not split equally.And, the ratio of V1 and V2 indicates the location of the fault along the string.
6. For the system shown, the fault is located between modules 1 and 2.Therefore, V1 = 100 10 V
V2 = 300 10 V
7. Ratio of V1 and V2 is 1:3. Therefore the ground fault is located after module #1.For further assistance contact FRONIUS tech support.
FRONIUS tech supportPrevious page
© Fronius 01/2006FRONIUS GFDI
FRONIUS technical support
For more information please don’t
hesitate to contact
FRONIUS technical support
phone: 810 220 4414
fax: 810 220 4424
www.fronius-usa.com
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