PYQs Based test 13: Power Systems

The undesirable property of an electrical insulating material is

A power system with two generators is shown in the figure below. The system (generators, buses and transmission lines) is protected by six overcurrent relays R ₁ to R ₆. Assuming a mix of directional and non-directional relays at appropriate locations, the remote backup relays for R ₄ are

A single-phase transformer of rating 25 kVA, supplies a 12 kW load at power factor of 0.6 lagging. The additional load at unity power factor in kW (round off to two decimal places) that may be added before this transformer exceeds its rated kVA is __________.

Five alternators each rated 5 MVA, 13.2 kV with 25% of reactance on its own base are connected in parallel to a busbar. The short-circuit level in MVA at the busbar is_________.

A distribution feeder of 1 km length having resistance, but negligible reactance, is fed from both the ends by 400 V, 50 Hz balanced sources. Both voltage sources S₁ and S₂ are in phase. The feeder supplies concentrated loads of unity power factor as shown in the figure.



The contributions of S₁ and S₂ in 100 A current supplied at location P respectively, are