Pid Repair; Insulation Monitoring Function; Introduction; Simple Troubleshooting - Sungrow SG1250UD Operation Manual

8. Inverter Functions

8.10.3 PID Repair

Please make sure the "PID power mode" in the protection parameter of the
inverter is "Repair" when enabling the manual PID repair function.
If the inverter is in deep standby state or the repair process is interrupted, the user can
enable the repair function manually from the LCD as follows:
Tap "Function" from the default menu.
Step 1
Tap "Setting".
Step 2
Step 3 Tap "Protect parameter" after entering the correct password.
Step 4 Click Next to find the page with "Manual PID repair" and click to enable the manual repair.
When the device is in "initial standby" state and the PID mode is repair and the DC voltage
is below 100V, you can start the device PID repair function by enabling the "Manual PID
repair".
If there is Key stop or Emergency stop or a device fault during the repair
process, the repair process will automatically stop.
8.11

Insulation Monitoring Function

8.11.1 Introduction

Insulation resistance is an important parameter related to safe operation. If the insulation
resistance is low, the direct contact protection and indirect contact protection may be failed;
meanwhile the fault current against the ground and the short circuit caused by low
insulation resistance may lead to electric fire, device damage or even physical hazards.
Sungrow's inverter is equipped with insulation resistance monitoring function to detect the
system insulation resistance in real time. For optional anti-PID function, the insulation
monitoring only monitors the system insulation resistance before the device is connected to
the grid. If the resistance is detected to be low, it will send alarm at the first time to remind
the user and prevent potential hazards.
The insulation monitoring function can be divided into two kinds:

For inverter without the anti-PID function or inverter is equipped with this function but it
is disabled, both the negative insulation resistance and positive insulation resistance
against the ground should be detected.

For inverter with the anti-PID function and this function is enabled, the DC negative and
the ground is equipotential. Therefore, only the positive insulation resistance to the
ground needs to be detected.

8.11.2 Simple Troubleshooting

Regardless of the inverter setting, when the insulation resistance is below the threshold
(settable from the LCD display), the inverter will send alarm signal and the Operation LED
will turn to yellow. After receiving the "low insulation resistance" alarm signal, the user
should stop the device and check the specific insulation resistance from the LCD screen
"Function/Run-information/Real time data".

If the insulation resistance recovers to normal, the fault loop is on the AC side.

If the insulation resistance is still low, the fault loop is on the DC side.
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Operation Manual