The auto-producer panel is the point at which a facility generating its own electricity connects to the grid. Generation sources such as a solar plant, a cogeneration unit or a generator set are paralleled with the network through this panel.
The panel carries both protection and measurement duties. After the disconnector and circuit breaker, the current transformer is connected in series with the main circuit; the voltage transformer sits on a shunt branch, meaning the generated current does not pass through it — the transformer only samples the voltage.
With both measurements available, the energy meter and the synchronisation relay can be supplied. Paralleling with the grid cannot take place until voltage and phase agreement have been confirmed.
An earthing switch is fitted on the cable side for maintenance. Anti-islanding protection is additionally required on the generation side: if the grid supply is lost, the generation source must be prevented from continuing to energise the network.
