Grid impedance calculation is a very broad and complex topic with values that vary quite a bit depending on the specific part of the power network you are looking at (transmission voltage, cable length, overhead/underground, transformer losses, load type and profiles, etc).
I don't ever remember seeing a value for average grid impedance due to the enormous complexity in even calculating the impedance of a small part of the grid and the horrendously complex and ever-changing interaction of the different parts of the grid.
It may be listed in an international standard or some grid network engineer's documentation somewhere, but it isn't a very useful figure to know. Are you just after figures for average losses such as the following example?
Grid power factor also varies, but on average should be around 0.9 (that's 0.9 lagging due to the large inductive element + small resistive element + very small capacitive element of the loads and power transmission and distribution network). The overall power factor will never be unity or leading power factor; the best you can hope for is close to unity (say 0.98 PF).
I want to connect to the grid a 2.5 kW wind turbine. I need to know
the current draw so I can size the turbine's rotor to the
torque and power requirements. Is the below pdf accurate, and applicable to my grid impedance question? Thanks for your input.
In this simple application you don't need to know or worry about the grid impedance at all. The controller/converter that connects the wind turbine to the grid effectively handles it all and you can feed up to 2.5kW (the full power rating of the wind turbine) into the grid continuously if need be. The grid is an active 'load' that can take as much power as you can put in, certainly when discussing a tiny 2.5kW turbine (that's the whole point of having apparent power and power factor).
There are plenty of guides on the internet for grid-connecting home wind and solar generation and they don't mention grid impedance at all (so I don't know where you got the idea you need to know it).
Also see previous threads on CR4 on home grid connected wind turbines for more information. Wikipedia also has very good overviews on the subjects of the power grid, power factor and wind turbines so don't forget to look there also.
Is the below pdf accurate, and applicable to my grid impedance question? Thanks for your input.
mycite.omikk.bme.hu/doc/54632.PDF
No. This is a very, very brief overview of certain aspects (Specifically soil resistivity variation) to do with calculating HV substation grid resistances for the purpose of estimating short circuit fault currents due to a phase to ground fault.
Grid Impedance
Re: Grid Impedance
