For a generator differential relay, protecting the three phases by only 1 relay, Im-0.01 A, I.RN =0.05A, I.set-D0.05A , the CT rati Kn-400/1, calculate the „minimum fault detectable I.f=? A A 128 O A 110 A 100 A 64 O A 48 O

in 50 kVA star connected 440 volts, three phase 60Hz alternator the effective armature resistance is 0.25 ohm per phase, the synchronous reactance is 3.2 ohm per phase and leakage reactance is 0.5 ohm per phase. detyermine at rated load and unity power factor: determine the percentage regulation on full load

A star-connected, 3-phase, 15 MVA, 3.3 kV alternator is protected by Merz Price circulating-current principle using 1000/5 amperes current transformers. The star point of the alternator is earthed through a resistance of 8 ohm. If the minimum operating current for the relay is 0.5 A, calculate the percentage of each phase of the stator winding which is unprotected against earth-faults when the machine is operating at normal voltage.

60 – MVA,15 – kV Problem 4 (Questions 21 through 23)-Two identical synchronous machines, each rated with a subtransient reactance of 0.1 py, are connected through a line of reactance 0.1 pu on the base of the machines rating. One machine is acting as a synchronous generator, while the other is working as a motor drawing 45-MW at 0.80 PF leading with a terminal voltage 14.5-kV. A symmetrical three-phase fault occurs at the motor bus. Calculate the following: 21. The generator fault current contribution (Ru.) is 22. The motor fault current contribution (p.u.) is 23. The total fault current is