26-05-2020, 06:06 AM
"Non zero impedance" is exactly what it says. It means the mains voltage will change if you put on a load. Impedance rather than resistance because there may be an inductive or capacitative component as well as resistive.
In a lot of power engineering work it's convenient to assume what's usually called "infinite busbars". In other words the load or power source you're connecting to the grid has a negligible effect on the grid voltage. In other words that's zero impedance. In the real world it's not true and often it really matters. If you're connecting a generator (conventional, PV, wind etc) to the grid at low voltage (400V/230V) then that bit of the grid has to be "stiff" enough to accept the power without the voltage changing too much. It's a real problem in areas with lots of domestic PV where in the limit power needs to flow backwards through the local substation.
In a lot of power engineering work it's convenient to assume what's usually called "infinite busbars". In other words the load or power source you're connecting to the grid has a negligible effect on the grid voltage. In other words that's zero impedance. In the real world it's not true and often it really matters. If you're connecting a generator (conventional, PV, wind etc) to the grid at low voltage (400V/230V) then that bit of the grid has to be "stiff" enough to accept the power without the voltage changing too much. It's a real problem in areas with lots of domestic PV where in the limit power needs to flow backwards through the local substation.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
