Q on Demand 24/7

With the "Q on Demand 24/7" function, the inverter remains connected to the utility grid overnight and is supplied with power via the utility grid in order that it can provide reactive power. When connected overnight, the inverter only draws an insignificant amount of active power from the utility grid to supply its internal assemblies. Depending on grid conditions and PV module characteristics, the inverter can provide up to 100% of its rated power as reactive power. The provision of reactive power during feed-in operation leads to a reduction of the feed-in power. This means that at 100% reactive power, the feed-in power is 0%. If the inverter is disconnected from the utility grid outside of feed-in operation, the "Q on Demand 24/7" function is not active. The "Q on Demand 24/7" function can only be restarted once there is sufficient PV power at the DC inputs of the inverter, meaning that the inverter can briefly switch back to feed-in operation at least once.

If the “Q on Demand 24/7” function is activated for longer than 24 hours, a self-test is performed. The inverter is disconnected from the utility grid for a few minutes. The self-test should be carried out at a time when the sun is shining. As soon as enough DC power is available, the PV inverter starts operating again. The time for the self-test is set via the parameter Time of cyclic insulation measurement.

The general setting of the grid management services (e.g. cos phi setpoint or Q(V) characteristic curve) can not be fully set independently of the "Q on Demand 24/7" function via the relevant parameters - "Q on Demand 24/7" only permits Q specifications. It is to be noted here that certain settings can have an influence on other grid-support settings and functions.

This means that if the "Q on Demand 24/7" function" is active, no other grid-supporting functions (e.g., cos phi) are possible between day and night operation of the inverter. Should an independent reactive power provision be desired between day- and night operation, the reactive power provision must be communicated to the inverter via a superordinate control unit.

The function "Q on Demand 24/7" is not compatible with the reactive power modes cos φ(P) charac. curve or cos φ(V) charac. curve.

The provision of reactive power can only be read off in the instantaneous values (GridMs.TotVAr, Reactive power) or requested via Modbus.

You can set the reactive power mode using the following parameters.