Problem 4 (10%), Find the TD of relays (B) such that these relays operate 0.3 seconds after relays (A) for a three-phase fault as indicated in Figure 2. Do the calculations for two cases: a) considering that relays A have an instantaneous element; and b) without considering instantaneous element. (The relays do not have short-delay definite-time elements.)

Fig: 1

Fig: 2