EE - Power Systems

For a single line to ground fault the zero sequence current is given by j3.0 pu. The current carried by the neutral during the fault is,

The per unit value of a 2 ohm resistor at 100 MVA base and 10 KV base voltage is,

The line currents in amperes in phases a, b and c respectively are 500 +j150, 100-j600 and -300+ j600. Determine the zero-sequence component of phase a current.

Two-wattmeter method is applied to a 3-phase motor running at full-load. Two wattmeters indicate 85.5 kW and 34.7 kW, respectively. What is the operating power of the motor?

In a 13.8 kV, 10 MVA base three phase system a phase to phase fault occurs. If the Thevin's equivalent impedance of the system is 2.63%, what is the magnitude of the fault current?

Consider a system with sequence impedances of Z1 = j0.2577 pu , Z2 = j0.2085 pu and Z0 = j0.14p, determine the fault current la1 for a single line to ground fault at A.

A 150 MVA, 13.8 kV, Y-connected 3 ϕ, 60 Hz alternator is operating at rated voltage and at no-load when a three-phase fault occurs at its terminals. If the subtransient reactance of the alternator is j 02 p.u., calculate the current at the instant the fault occurs.

A 150-MVA, 13.8-KV, Y-connected, 3φ , 60-HZ alternator is operating at rated voltage and at no-load when a threephase faults occurs at its terminals. If the sub transient reactance of the alternators is j0.2 pu, calculate the current the instant the fault occurs.

Power in a balanced 3-phase system is produced by two wattmeter method and it is found that the ratio of the two wattmeter readings is 2 is to 1. What is the power factor of the system?

A 220 V, 3-phase, 4 wire abc system supplies unbalanced wye-connected resistances of Ra = 10 ohms, Rb = 15 ohms, and Rc = 20 ohms. Determine the total power of the system.

A balanced delta connected load of (4 + j3) Ω per phase is connected to a three-phase, 230 V supply. Find the total kVA.

A load of 10,000 kVA, 80% lagging is connected to a 13,200-volt line. How much capacitive reactive power is needed to correct the power factor to 97% lagging?

A balanced delta connected load draws 100 A line current from a balanced 3 phase supply. Determine the zero sequence components of the currents.

In two-wattmeter method of power measurement, the reading of the two wattmeters were 6717 watts and 2658 watts, respectively. Find the power factor.

A balanced delta connected load of 15 + j18 ohms per phase is connected at the end of a three-phase line. The line impedance is 1 + j2 ohms per phase.