Question

In: Electrical Engineering

Diesel Generator A I MVA diesel three-phase generator is rated at 4.16 kV, 60 Hz, and...


Diesel Generator A I MVA diesel three-phase generator is rated at 4.16 kV, 60 Hz, and connected as Y its neutral is kept floating. It is directly tied to three loads, one consuming 50% of its capacity, and each of the other two consuming 25% of its capacity. A three-phase to ground fault could occur at any of the loads. Draw a one-line diagram of this system, then describe what type of faults could occur in the generator and diesel engine. Explain at least three types of protection strategies that have to be implemented in such a system, and show necessary fault current calculations. Assume that any fault impedance you may need is 9.02 pu, and any component impedance is 0.4 pu.

Solutions

Expert Solution

Solution:


Related Solutions

2) A three-phase synchronous generator is rated 16 kV and 200 MVA, has negligible losses and...
2) A three-phase synchronous generator is rated 16 kV and 200 MVA, has negligible losses and has reactance of 1.65 pu. The generator is operated on an infinite bus of 15 kV voltage and delivers 100 MVA at 0.8 Power Factor, lagging. a)Determine the internal voltage (E_i), the power angle (δ), and the line current of the machine. b)If the field current of the machine is reduced by 10%, while the mechanical power input to the machine is maintained constant,...
A three-phase synchronous generator is rated 16 kV and 200 MVA, has negligible losses and has...
A three-phase synchronous generator is rated 16 kV and 200 MVA, has negligible losses and has reactance of 1.65 pu. The generator is operated on an infinite bus of 15 kV voltage and delivers 100 MVA at 0.8 Power Factor, lagging. a)Determine the internal voltage (E_i), the power angle (δ), and the line current of the machine. b)If the field current of the machine is reduced by 10%, while the mechanical power input to the machine is maintained constant, determine...
6.9 A3 ϕ, 11 kV, 60 Hz, 25 MVA, Y-connected cylindrical-rotor synchronous machine generator has Ra...
6.9 A3 ϕ, 11 kV, 60 Hz, 25 MVA, Y-connected cylindrical-rotor synchronous machine generator has Ra = 0.45 Ω per phase and Xs = 4.5 Ω per phase. The generator delivers the rated load at 11 kV and 0.85 lagging power factor. Determine the excitation voltage, Ef, for this operating condition. 6.11 The synchronous machine in Problem 6.9 is operated as a synchronous motor and it is drawing rated MVA at 0.85 lagging power factor. Determine the excitation voltage, Ef,...
A three-phase 60-Hz transmission line is energized with 420 kV at the sending end. This line...
A three-phase 60-Hz transmission line is energized with 420 kV at the sending end. This line is lossless and 400 km long with ? = 0.001265 rad/km and ?? = 260 Ω. a) Suppose a three-phase short-circuit occurs at the receiving end. Determine the receiving end current and the sending end current. b) Determine the reactance and MVar of a shunt reactor to be installed at the load bus to limit the no-load receiving-end voltage to 440 kV. c) When...
A 1000MVA, 20kV, 60 Hz three phase generator is connected to an infinite bus through a...
A 1000MVA, 20kV, 60 Hz three phase generator is connected to an infinite bus through a 1000MVA, 20kV? / 345kVY transformer to a 345kV circuit breaker and a 345kV transmission line. The generator reactances are X``d=0.17, X`d=0.30, and Xd=1.5 per unit on a 1000MVA, 20kV base. Generator time constants are T``d=0.05 seconds, T`d=1.0 seconds, and TA=0.10 seconds. The transformer series reactance is 0.10 per unit on the transformer ratings as a base. Neglect transformer losses, excitation current, and transformer time...
A 35 km, 34.5-kV, 60-Hz three phase line has a positive-sequence series impedance z = 0.10...
A 35 km, 34.5-kV, 60-Hz three phase line has a positive-sequence series impedance z = 0.10 + j0.40 Ohms/km. The load at the receiving end absorbs 15 MVA at 33 kV. Assuming a short line, calculate: (a) the ABCD parameters, (b) the sending-end voltage for a load power factor of 0.95 lagging, (c) the sending-end voltage for the a load power factor of 0.9 leading. (d) For which case is the sending-end voltage higher?
A three phase, 60 Hz, 480 V, Y-connected, two-pole synchronous generator has a synchronous reactance of...
A three phase, 60 Hz, 480 V, Y-connected, two-pole synchronous generator has a synchronous reactance of 0.95 Ω per phase. Its armature resistance is negligible. Its combined friction and windage losses are 1.3 kW and its core losses are 0.95 kW. The field current is constant at no-load. Its full load armature current is 55 A at 0.9PF lagging. Assume phase voltage is a reference. Determine following: a) Its terminal voltage when it is loaded with the rated current at...
8. Three 6.6 kV, 12 MVA, 3-phase alternators are connected to a common bus bars. Each...
8. Three 6.6 kV, 12 MVA, 3-phase alternators are connected to a common bus bars. Each has reactance to positive sequence current of 15%. The reactance to negative and zero sequence current are 75% and 30% of the positive sequence value. If an earth fault occurs on one of bus bar, determine the fault current when one of the alternator neutral is earthed through a resistance of 0.25 ohm and the others are isolated. 9. Four identical alternators each rated...
Problem 3: A single phase 60 Hz two-winding power transformer is rated at 2400V/240V and 100...
Problem 3: A single phase 60 Hz two-winding power transformer is rated at 2400V/240V and 100 kVA with Zeq = 0.5 + j0.8 Ohm. If an autotransformer is built from this conventional transformer to supply a load at 2640V with supply voltage 2400V. Draw the autotransformer and calculate Zeq, the voltage, current and apparent power rating of the auto transformer. Also calculate the apparent power rating advantage of autotransformer over conventional transformer.
A three-phase motor is delta connected to a 415 V, 60 Hz line. If the line...
A three-phase motor is delta connected to a 415 V, 60 Hz line. If the line current is 25 A and the motor power factor is 0.75, how much power is consumed by the motor (a) Determine the size of the bank of three capacitors to improve the power factor of the motor to 0.95. The capacitors are delta connected. (b) If two of the motors work together, what is the size of capacitors to correct the power factor to...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT