An interconnection reactor system is shown in fig.. The base values for the given percent reactances are the ratings of the individual pieces of equipment. A three phase short circuit occurs at point F. Determine the fault current and fault KVA if the bus-bar line to line voltage is 11 kV. 10MVA 10%. G₁ 20MVA 15% G₂ X1 -0000 10MVA 5% 20MVA 15% G3 -0000 8MVA 4%

Supposed a 5000 kva, 13.8 volt, 60 hz, 3-phase capacitor bank with grounded neutral is being switched through a circuit breaker, through a source of 1 millihenry. what is the peak current at restrike voltage?

Q2. The single-line diagram of a simple three-bus power system is shown in Figure-2. Each generator is represented by an emf behind the sub-transient reactance. All impedances are expressed in per unit on a common MVA base. All resistances and shunt capacitances are neglected. The generators are operating on no load at their rated voltage with their emfs in phase. A three-phase fault occurs at bus 3 through a fault impedance of Zf = j0.19 per unit. (i) Using Th'evenin's theorem, obtain the impedance to the point of fault and the fault current in (ii) Determine the bus voltages per unit. ) j0.05 j0.075 j0.75 2 j0.30 j0.45 Figure-2: Single line diagram of the power system network for Q2 3

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What are the hazards of phase failure and phase reversal?

Id is :  510221

A 60 Hz, 33 kV, 3-phase alternator with earthed neutral has a reactance of 7 ohms per phase and is connected to a bus-bar through a circuit breaker. The distributed capacitance upto circuit breaker between phase and neutral in 0.03 uF. Determine   (i) peak re-striking voltage across the contacts of the breaker   (ii) frequency of oscillations

A 13.2 kV, 60 Hz, 3-phase synchronous generator is connected in star and its neutral point is earthed while inductance per phase is 0.02 Henry. The generator is connected to a bus bar through a circuit breaker. The distributed capacitance up to circuit breaker between phase and neutral is 0.015 micro Farad. Determine the following: (i) Peak re-striking voltage (in kV) across the contact of circuit breaker; (ii) Frequency of oscillations (in kHz); (iii) Time to occurs first peak re-striking voltage (in micro second) and (iv) The average rate of rise of re-striking voltage (in mega volts per second)

Problem #2: A transformer is fed from a generator via a 5-cycle breaker. Generator reactance are: X"=18%, X'=25%, Xe=120%. A three-phase fault occurs at the load side of the breaker when the transformer was unloaded. Find: A)The sustained short circuit current in the breaker. B) Initial symmetrical rms current in the breaker. C) Maximum dc short circuit component in the breaker.

The step down DC chopper uses DC source voltage V(dc) = 200 V and resistive load impedance of 10 ohm. The duty cycle is 0.4 the voltage drop across the switch may be taken as zero, Calculate :   (a) Average and RMS value of output voltage.  (b) Average and RMS value of output current.