plaese I want the soulotion by clear writting or text and st

plaese I want the soulotion by clear writting or text and step by step

For the system shown in figure 2.1, directional relays are used at breakers CB2, CB4 and CBS .Over current relay is CB1. For a fault at F1 (bus1), what protective device detects the default? For a fault at F3 (bus3), what protective device detects the default ?

Solution

For a fault at bus 1.

If the fault ( line to earth / line to line ) causes a shortage of current then the over current relay works and detects the fault.

For a fault at F3… bus 3, depending on the distance from the fault location , the directional relays can get triggered.