Prepare this information before contacting SolarEdge

–

• Model and serial number of the product in question.

• The error indicated on the product SetApp mobile application or on the monitoring platform or by the LEDs, if there is such an indication. 

• System configuration information, including the type and number of modules connected and the number and length of strings. 

• The communication method to the SolarEdge server, if the site is connected. 

• The product's software version as it appears in the status screen.

What is an Isolation Fault?

In photovoltaic systems with a transformer-less inverter, the DC is isolated from ground. Modules with defective module isolation, unshielded wires, defective power optimizers, or an inverter internal fault can cause DC current leakage to ground (PE - protective earth). Such a fault is also called an isolation fault.

Location of the Isolation Fault

The value of the isolation resistance (in kΩ) indicates whether the fault is at DC+ or DC-:

• 0% indicates the fault is at the DC+ side

• 100% indicates the fault is at the DC- side

To identify the location of the faulty Power Optimizer:

Multiply the number of Power Optimizers in the string by the percentage value. The result is the module near which the fault occurred.

For example: In a string with 15 modules and Power Optimizers and a percentage value of 68% :
15*68% = 10.2

This means that the fault is near module #10, counted from the DC+ side.

Troubleshooting an Isolation Fault with SetApp using an Insulation Tester

• Step 1
  Turn OFF the Inverter
  Turn OFF the inverter ON/OFF switch, and wait until SetApp indicates that the DC voltage is safe (<50V), or wait five minutes before continuing to the next step. 

• Step 2
  Disconnect DC
  Disconnect all the DC cables connecting the strings to the inverter or the Safety Switch. 

• Step 3
  Test the Resistance
  Test the resistance of the extension DC cables between the strings and the inverter (home-run cables):

  1. Disconnect the home-runs at both ends and measure each wire by connecting it to the positive probe, while the negative probe remains connected to the ground.

  2.  If the wiring resistance is less than 200MΩ, the wire is faulty; replace any faulty wires. 

  3. If the wiring resistance is 200MΩ or more, the fault is in the string that was connected to this extension cable;
     check the string (without the extension cable) as described in the following step.

Testing the String Itself:

• Step 4
  Test the String Resistance

  1. Verify safe string voltage and current: max. 50V and 500mA.

  2. Connect the positive and negative connectors of the first or last Power Optimizer in the string to the branch cable

  3. Connect the positive probe of the insulation tester to the branch cable. 

  4. Connect the negative probe of the insulation tester to a ground point.

  5. Select 500V testing on the insulation tester.

  6. Test the insulation.

• Step 5
  String Insulation Results
  If the resistance is less than 600kΩ in a single phase inverter or less than 1MΩ in a three phase inverter, a leakage is occurring. Continue checking this string’s components to isolate the source of leakage, as detailed in the following steps.

Test the Power Optimizer's and Module's Resistance:

• Step 6
  Test the Power Optimizers and Modules

  1. Disconnect the Power Optimizer from the string; it should remain connected to the PV module

  2. Verify safe Power Optimizer voltage and current: max. 1V and 500mA

  3. Connect the Power Optimizer’s positive and negative output connectors to the branch cable

  4.  Connect the positive probe of the insulation tester to the branch cable.

  5.  Connect the negative probe of the insulation tester to a ground point.

  6. Select 500V testing on the insulation tester and measure the resistance.

• Step 7
  Power Optimizer and Module Results
  If the measured resistance is 200MΩ or more, the Power Optimizer and module are not faulty.
  If the measured value is less than 200MΩ, the Power Optimizer, the module or both are faulty. Continue checking as detailed in the following steps in order to know which one is faulty:

Test the Power Optimizers Resistance:

Find whether the leakage is from the module or from the Power Optimizer. Test each component individually by measuring the resistance between negative wires and ground:

• Step 8
  Testing the Power Optimizer

  1. Disconnect the module from the Power Optimizer

  2. Connect the power optimizer’s positive and negative output connectors to the branch cable

  3. Connect the positive probe of the insulation tester to the branch cable

  4. Connect the negative probe of the insulation tester to the power optimizer frame (ground point)

  5. Select 500V testing on the insulation tester

  6. Measure the resistance.

• Step 9
  Power Optimizer Test Results
  If the value is 200MΩ or more – the Power Optimizer is fine, but the module is faulty.
  
  
  If the value is less than 200MΩ, replace the Power Optimizer and test the module in case it is also faulty, as described in the next step.

Test the Module's Resistance:

• Step 10
  Connect the Module
  Disconnect the branch cable from the power optimizer and connect it to the module:

• Step 11
  Test results
  Measure the resistance:

  • If the value is with 40MΩ*m2 or more – the module is OK.

  • If the value is less than 40MΩ*m2, the module is faulty.

  • The typical value is 80MΩ for each module.

Onsite Power Optimizer Troubleshooting

• Step 1
  Pairing
  If the Power Optimizer is not recognized by the inverter, initiate the Pairing process. After pairing is complete, wait 15 minutes for the inverter to try and recognize all the Power Optimizers.

• Step 2
  Test Power Production
  Test if the Power Optimizer is producing power by using a Current Clamp on the input cables and check for current.

Before you proceed, switch the Inverter ON/OFF switch to OFF and wait until the DC voltage drops below 50V. 

Test Power Optimizer connection and output voltage

• Step 3
  Check Polarity
  Check that the Power Optimizer is not connected in a reverse polarity or has a loose connector. If you find a reverse polarity connection or a loose connection, fix the connection and try pairing again. 

• Step 4
  Measure output voltage
  If the connection is OK: Disconnect the Power Optimizer from the string (not from the module) and measure the output voltage of the Power Optimizer:
  
  Connect the (+) probe to the Power Optimizer (+) output connector and (–) probe to the optimizer (–) output connector
  
  If 𝑽𝒐𝒖𝒕 < 𝟎.9𝑽 - Replace the Power Optimizer
  If 𝑽𝒐𝒖𝒕 > 𝟏.1𝑽 - Replace the Power Optimizer

Test the Power Optimizer resistance

• Step 5
  Resistance test
  If 𝑽𝒐𝒖𝒕 is correct (in range 𝟎.9v to 𝟏.1 v), disconnect the Power Optimizer from the string and module and perform the following Resistance tests.
  If any of the following tests show under 100 Ω, replace the Power Optimizer:

• Step 6
  Input resistance test
  Test the Input (short Power Optimizer cables): Connect the (+) probe to the Power Optimizer (+) input connector and (–) probe to the Power Optimizer (–) input connector

• Step 7
  Output resistance test
  Test the Output (Power Optimizer long cables): Connect the (+) probe to the Power Optimizer (+) output connector and (–) probe to the Power Optimizer (–) output connector

Test the PV module output voltage (Voc)

• Step 8
  Measure module voltage
  Measure the Voc (output voltage) of the module and compare the results to the module datasheet - a different value means there is an issue with the module. 

Diode Test

• Step 9
  Input Side Diode Test
  Switch your multimeter to "Diode Test Mode",
  Test the Input (short Power Optimizer cables ): Connect the (+) probe to the Power Optimizer (+) input connector and (–) probe to the Power Optimizer (-) input connector.
  The correct voltage reading should be ~1.0V.

• Step 10
  Input Side Diode Test - Reverse Polarity
  Test the Input: Connect the (+) probe to the Power Optimizer (-) input connector and (–) probe to the Power Optimizer (+) input connector.
  The correct voltage reading should be O.L (open circuit).

• Step 11
  Output Side Diode Test
  Test the Output (long Power Optimizer cables ): Connect the (+) probe to the Power Optimize (+) output connector, and (–) probe to the Power Optimizer (-) output connector.
  The correct voltage reading should be ~0.5V

• Step 12
  Output Side Diode Test - Reverse Polarity
  Test the Output: Connect the (+) probe to the Power Optimizer (-) output connector, and (–) probe to the Power Optimizer (+) output connector.
  The correct voltage reading should be O.L (open circuit)

• Step 12
  Output-Input Diode Test
  Test the Input-Output: Connect the (+) probe to the Power Optimizer (+) input connector and (–) probe to the Power Optimizer (+) output.
  The correct voltage reading should be O.L (open circuit)

Updating the Monitoring Platform

Follow the steps below to update the serial number of a replacement  Power Optimizer.

• Step 1
  Go to the PV site in the SolarEdge Monitoring Platform.

• Step 2
  Click the Admin tab

• Step 3
  Click Logical Layout

• Step 4
  Scroll down the list to the Power Optimizer that was replaced and select it.

• Step 5
  Once the Power Optimizer is selected, click Replace.

• Step 6
  Enter the serial number of the newly installed Power Optimizer.
  Enter the last 10 digits of the Power Optimizer's serial number in the following format: XXXXXXXX-XX.  For example: for serial number SF0112A-07F123456-1B you should enter: 7F123456-1B

• Step 7
  Click Save

• Step 8
  That's it!
  The new serial number will be displayed next to the module in the logical layout.