Q2. The following figure shows the protective circuit for an 11 kV radial feeder. The respective short [1+3+3] circuit c

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Q2 The Following Figure Shows The Protective Circuit For An 11 Kv Radial Feeder The Respective Short 1 3 3 Circuit C 1 (70.7 KiB) Viewed 29 times

Q2. The following figure shows the protective circuit for an 11 kV radial feeder. The respective short [1+3+3] circuit currents (Isc) at the bus 1, 2 and 3 are as shown in the Fig. Q2. The current tap setting for the relay R3 is 125% and the current tap setting for the other two relays is 150%. Relay R2 provides backup protection for relay R3 and relay R₁ provides backup protection for relay R₂. Time discrimination between primary relays and the backup relays must be 0.45 seconds. The time multiplier setting for the relay R3 is set at 0.1. (a) Determine the time required for the relay R3 to operate. (b) Find the time multiplier setting and time of operation required for the relays R2 and R1. 1 2 3 CT CT, CT3 400/5A 200/5A 200/5A 이 이 이 R₁ R, R₂ Lisc = 3200 A Izsc =3000A Fig. Q2: The protective circuit for an 11 kV radial feeder 11kV 13SC = 2500A