Question

The three impedances Z1 = 20∠30⁰Ω, Z2 = 40∠60⁰Ω, Z3 = 10∠-90⁰Ω are delta-connected to a 400V, 3 – Ø system. Find the line current I2.

(a) (-27.32+j10) A

(b) (27.32+j10) A

(c) (-27.32-j10) A

(d) (27.32-j10) A

The question was posed to me in exam.

I'm obligated to ask this question of Three-Phase Unbalanced Circuits in section Polyphase Circuits of Network Theory

Answer 1

Correct option is (a) (-27.32+j10) A

For explanation: The line current I2 is the difference of IY and IR. So the line current I2 is I2 = IY – IR = (-27.32+j10) A.