Question 1. FIGURE 1 shows four generators feeding into a sectionalised busbar with a fault limiting reactor.

FIG. 1

Each generator is rated at 11 kV and 30 MVA and has a reactance of 0.2 p.u.

Calculate the value of the reactance to limit the fault level on a feeder to 500 MVA.

Question 2. FIGURE 2 shows the sectionalised busbar of a two generator power station connected to the national grid.

Calculate, using a 40 MVA base, the fault level for a 3-phase symmetrical short circuit on the 11 kV feeder.