Power Station Unit

Which PTW studies take into account the Power Station Unit, and how is it taken into account?

The Pg and Pt fields (power station units) are the range of voltage adjustment which is used for the Generator and Transformer impedance correction factor when the power station unit is without an on-load tap changer. These are used for the calculation of short circuit I"k in IEC 60909.

In equation 24 from IEC 60909-0, Ugmax = UrG (1 + Pg) is used instead of UrG for the correction factor:



See Section 3.7.2 on the IEC 60909-0 standard for further details. This only applies for Power station units only (Generator+Transformer combination). If you do not want to consider it as a power station unit, insert a small impedance in between the generator and bus or transformer and bus.