2. © Fronius 01/2006 FRONIUS 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.

3. © Fronius 01/2006 FRONIUS GFDI FRONIUS Ground Fault Detection and Interruption Installation instructions Troubleshooting What is a ground fault? Contact FRONIUS tech support

4. © Fronius 01/2006 FRONIUS 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. L1L2L1L2 = ~ GND  Main pageInstallation instructions + -

5. © Fronius 01/2006 FRONIUS 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

6. © Fronius 01/2006 FRONIUS GFDI AC/DC ground terminal Previous page = ~ GND A + - L1L2L1L2 GFDI fuse Main page

7. © Fronius 01/2006 FRONIUS GFDI Ground fault troubleshooting Ground fault detection system operation: DC negative is grounded through the 1 A GFDI fuse. = ~ GND  A A When the ground fault current exceeds 1 A, the ground fault fuse opens and the inverter shuts down with STATE Code: 434 434 troubleshooting + - L1L2L1L2 Main page

8. © Fronius 01/2006 FRONIUS GFDI STATE 434 troubleshooting Ground fault LED ON Ground fault LED OFF Main page

9. © Fronius 01/2006 FRONIUS GFDI STATE 434: Ground fault LED ON STATE 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  V 1. Between DC Negative terminal and Ground terminal  V 2. Continue…Main page

10. © Fronius 01/2006 FRONIUS GFDI State 434: Ground fault LED ON (continued) From the previous page, if V 1 is approximately equal to V 2 (±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 & V 1 = V 2 ), please contact FRONIUS tech support: Continue… V1V1 V2V2 If V 1 is not equal to V 2, then there is a ground fault in the system. Continue to next page… Previous page

11. © Fronius 01/2006 FRONIUS 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: V oc = 400 V V 1 = 400 V V 2 = 0 V When the GFDI fuse is removed, the voltages should divide approximately equally: V 1 = V 2 = V oc /2 Previous page

12. © Fronius 01/2006 FRONIUS 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 V 1 and V 2. 3. Again, when there is no fault in the string V 1 = V 2 = V oc /2. 4. Repeat steps 2,& 3 for each string. Since there is no fault on strings 1 and 2, V oc is split equally between V 1 and V 2. Assume there is a ground fault on the rightmost string. Follow the steps below to locate the fault: Previous page

13. © Fronius 01/2006 FRONIUS GFDI State 434: Ground fault LED ON (continued) 5. When there is a fault in the string, V oc does not split equally. And, the ratio of V 1 and V 2 indicates the location of the fault along the string. 6. For the system shown, the fault is located between modules 1 and 2. Therefore, V 1 = 100  10 V V 2 = 300  10 V 7. Ratio of V 1 and V 2 is 1:3. Therefore the ground fault is located after module #1. For further assistance contact FRONIUS tech support. FRONIUS tech supportPrevious page

14. © Fronius 01/2006 FRONIUS GFDI FRONIUS technical support For more information please don’t hesitate to contact FRONIUS technical support phone: 810 220 4414 fax: 810 220 4424 pv-us-support@fronius.com www.fronius-usa.com Main page