How it Works

1. Zero Export Device Technology

The technology incorporated into the ZED family delivers;
1. Inverter management of solar PV production
2. Maximum Solar PV production while minimising grid consumption
3. Zero export to the grid
4. Secondary protection as per AS 4777.3 2005 and IEC 60255-5 and IEC 60255-22

2. Inverter Control/Solar PV Production

The ZED devices communicate with the inverter via three (3) protocols, the choice of protocol is dependent on specific inverter compatibility. These protocols are 4 or 6 bit binary and RS 485 protocols.
The 4 bit binary provides 16 levels of solar PV production between 0 and 100%.
The 6 bit binary provides 64 levels of solar PV production between 0 and 100%.
RS 485 provides solar PV production in 1% increments.

2.1 Compatible Inverters

There is a range of compatible inverters that the ZED family of devices can manage Solar PV production and deliver Zero Export.
Inverters that can be controlled via 4 or 6 bit binary require a management card supplied by the inverter manufacturer; these are often referred to as a Power Control Module, Power Management Unit, Data Manager or controller.
Inverters that have RS 485/Modbus connection are managed via inverter specific protocols.
Inverter performance and compatibility with the ZED family has been validated by GNT Engineering.

To date a number of inverters have been validated by GNT Engineering and are managing Zero Export solutions for 3 phase and single phase installations.

2.2 Inverter List

4 Bit Binary - ABB, Fronius, SMA, Solar Edge, ZeverSolar*
6 Bit Binary - Fronius
MODBUS RS485 - ABB, Fronius, Schneider, GoodWe, Delta*, Omnik*, Samil * ZeverSolar*
*Under Development

3. System Management

Incorporating CT’s the ZED constantly monitors the load and or generation, the device constantly monitors this data resulting in communication with the inverters to generate the maximum amount of solar PV to best match the load profile. The technology incorporated into the device ensures that there is Zero Export to the grid.

4. Device Programming

The ZED requires to be programmed, at installation the device is connected to a computer and the system size and parameters are entered. Network protection settings are selected via a drop down menu where the appropriate network is selected and the protection settings are automatically activated for the selected network.
The web enable devices allow for real time monitoring as shown in the image below. Data is also sent to the cloud where clients can access historical data.