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GATE 2014 EE (EE1) – Question 51

Power Systems · Per-unit quantities, Bus admittance matrix, Gauss-Seidel and Newton-Raphson load flow methods · 2 marks · Multiple choice

The two-bus system shown supplies load 1.0 + j0.5 pu. Find V₁ (pu) and δ₂ respectively.

Diagram for GATE 2014 EE (EE1) question 51
  1. 0.95 and 6.00°
  2. 1.05 and −5.44°
  3. 1.1 and −6.00°
  4. 1.1 and −27.12°

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Show answer and explanation

Correct answer: (B) 1.05 and −5.44°

Explanation

Let V2=e^(jδ2), and load current be I=(1−j0.5)e^(jδ2). Then V1=V2+j0.1I=e^(jδ2)(1.05+j0.1). Since V1has angle0, δ2=−atan(0.1/1.05)=−5.4403°and |V1|=√(1.05²+0.1²)=1.05475. The closest choice is **1.05and−5.44°,B**. The bus1shunt affects generation, not this line-drop relation.