UK Grid Voltage (Connect and Disconnect Notifications)

In the UK the ideal operating conditions of the grid network is 230V+10%/-6% this gives a voltage range of 216.2V-253V.

The G98/G99 regulations state a very specific set of conditions for disconnections of the inverter from the grid network.

Should the grid voltage fall outside of these specifications the inverter will disconnect from the grid as a safety precaution and you will receive a Sunsynk Connect notification stating that your plant has disconnected:

After 60s the inverter will then try to reconnect to the grid, which will trigger a second notification:

If the grid voltage is still too high the grid relay will then disconnect again causing persistent notifications to both the installer and the end user.

Additionally, as there is nowhere for power to go if the batteries are fully charged this will cut out the PV power. Causing your power overview to look similar to the one below:

Unfortunately, as this disconnect occurs as a safety precaution in line with G98/G99 compliance we cannot stop these notifications.

YOU MUST NOT TAKE YOUR INVERTER GRID SETTINGS OUTSIDE OF G98/G99 THIS WILL EFFECT YOUR INVERTER COMPLIANCE WITH UK GRID REGULATIONS.

In some cases it is possible that your inverter may be set in the grid settings to G98/G99_NI which is grid standard for Northern Ireland, this has lower voltage tolerances than the UK mainland.

Please ensure that G98/G99 is enabled instead.

This is more persistent when PV is exporting. When PV is exporting a slight natural rise on the grid voltage will occur naturally due to the change in resistance in the local network cables.

If there are multiple properties connected to one transformer all exporting at the same time this natural increase is multiplied by the amount of properties causing a voltage rise.

Therefore, 0.2V rise from one property exporting PV can very easily become a 2V rise if 10 properties on the same transformer are exporting and this increase could take the unit outside of the set safe voltage parameters.

In areas with weaker grid connections that may experience high impedance may have even larger grid rises.

If you are experiencing these frequent notifications during times of high PV export then we advise you contact your District Network Operator (DNO), they will be able to perform a grid voltage assessment and take any necessary actions to reduce the grid voltage for your area.