In the circuit shown, the phase currents are A, A, A. Given that the CTs are ideal with no saturation, and the turns ratio of the Main CT is 300:5 and that of the Auxiliary Transformer (YnΔ) is 2:1 on every phase, the value of , rounded off to three decimal places, is:
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Three phase conductors carrying I_A, I_B, I_C pass through three Main CTs (300:5). The CT secondaries are star-connected: one end of each secondary goes to a common bottom bus, which is earthed. The other end of each goes out on its own lead to one of three relay resistors R, and the three R are star-connected at the right with their star point isolated. The current in the phase-A lead is I_AR. An Auxiliary Transformer (YnΔ, 2:1 on every phase) is connected in shunt: each star primary winding is connected from one lead to the earthed common bus, and the delta secondary windings are closed on themselves with no external load.
- (A)
0 A
- (B)
0.653 ∠17.556° A
- (C)
537.240 ∠4.105° A
- (D)
8.954 ∠4.105° A