Operator`s manual

3
Required Condition for Grid-connected Operation
The solar power conditioner meets the following requirements for connection to the grid:
1. Islanding Protection
The power conditioner will shut down if the power from the grid becomes abnormal or fails. This will provide safety to the
people working on power lines and protect the home circuits and power conditioner.
The solar power conditioner continually monitors the voltage and frequency of the grid through an internal control circuit. It will
detect an abnormal condition or failure of the grid. Abnormal conditions include AC overvoltage, AC undervoltage, AC
overfrequency, and AC underfrequency. The solar power conditioner immediately shuts down and disconnects from the grid
should any of the above conditions occur.
Per UL 1741, the solar power conditioner will stop within 2 seconds should the grid voltage be lower than 211V AC or higher than
264V AC. The solar power conditioner will stop within 1 second should the frequency of the grid be lower than 59.3Hz or higher
than 60.5Hz.
The solar power conditioner incorporates two functions to detect and prevent islanding operation. This is important when the
output of the power conditioner and the power consumption of the home are well balanced and the voltage or the frequency of the
grid does not change during a power failure, resulting in the power failure not detected. This is avoided with a passive system
that detects a jumping voltage phase, and an active system that detects frequency shift that stops the power conditioner
operation within 2 seconds.
The solar power conditioner display indicates grid-off status to indicate a power failure.
2. Ground Fault Detector Interrupter (GFDI)
The ground fault detector interrupter is the protection facility for the PV system which is required by UL1741. This function will
monitor the ground current of the PV array at the detect circuit, and if the current is more than 1A, the solar power conditioner
stops to shut down the ground current. The solar power conditioner display indicates ground fault status. In this case, the solar
power conditioner will not restart automatically and requires a manual start.
A fuse (rated 1A) will also detect the ground fault and if the fuse blows out by the ground fault, the solar power conditioner
display shows that status on the display.