Jul 25, 2018 - 09:59 PM
In Steady state/ slow front transient:
The busbar usually does not need to be modeled specifically. A wire connection (i.e. pure conductor) is generally sufficient. Earthing can be modeled by connecting one end of the earth resistor to your circuit and another end to the ground.
In Fast Front Transient:
If there are several circuit elements connected to a busbar and the fast front wave is expected to travel along the bus bar, it would be better to model it using a distributed parameter line (with correct representation of surge impedance, length, velocity).
Similarly, if a fast front lightning surge is expected to be incident on the power system, the line earthing should be modeled considering the current dependence of soil resistance.