A simple power system is shown in this Fig. The generator (480 V, 10 kVA) is connected to an ideal step-up transformer (1:10), a transmission line (R=20 Ohm and X=60 Ohm), step down transformer (20:1) and a load with magnitude Z=10 Ohm and angle =30 degree the base values for this system are chosen to be 480 V and 10 kVA at the generator. Calculate the per-unit impedance of the load. Calculate the per- unit current in the line Select one: a. 1.43 A b. 0.569 A c. None of the above d. 2.01

A simple power system is shown in this Fig. The generator (480 V, 10 kVA) is connected to an ideal step-up transformer (1:10), a transmission line (R=20 Ohm and X=60 Ohm), step down transformer (20:1) and a load with magnitude Z=10 Ohm and angle =30 degree the base values for this system are chosen to be 480 V and 10 kVA at the generator. Calculate the per-unit impedance of the load. Calculate the per- unit current in the line Select one: a. 1.43 A b. 0.569 A c. None of the above d. 2.01

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter2: Fundamentals

Section: Chapter Questions

Problem 2.21P: An industrial plant consisting primarily of induction motor loads absorbs 500 kW at 0.6 power factor...

See similar textbooks

Similar questions

generator (b) What is the average power dissipated in R? P=[ W Help Enter 500 v generator voltage -500 v AC Generator 0 Ideal Transformer R = 300 Rg8 time (a) The sinusoidal voltage output from the AC generator oscillates between 500 V and -500 V. The circuit for an ideal transformer is constructed with a generator, transformer and a 30 W resistor. The generator makes 6 loops with the transformer and the resistor makes 11 loops with the transformer (the figure does not show these loops accurately). What is the maximum voltage across the resistor R? V= V Help Enter
A 1200 kVA, 3.3-kV, three-phase, star-connected alternator has an effective resistance that is 1.5 times the dc resistance. The dc resistance is obtained by connecting two terminals to a dc source. The current and voltage are 87.6 A. and 6V, respectively. A field current of 30 A produces a current of 200 A on short-circuit and 1.1 kV on open circuit. a. Calculate the power angle and the total generated complex power when the generator is operating full-load of 1200 kVA at 0.9 pf lagging and at rated terminal voltage. Assume that flux varies as the field current. b. If the altenator is operating at the same excitation voltage as in (a), calculate the maximum kW output of the alternator.
Q1: The primary of a certain transformer takes 0.7 A at a power factor of 0.5 when it is connected across 200 V, 50 Hz supply and the secondary is on open circuit. The number of turns on the primary is twice that on the secondary. A load taking 10 A at a lagging power factor of 0.8 is now connected across the secondary. Calculate the primary current and power factor. Draw the phasor diagram.
A three stage Cockroft-Walton generator is supplied by 212.133 V, 50 Hz source via a transformer with turns ratio equals to 2/800. All capacitors have a value of (0.8 µF). The protection current equals to 15 mA. Find the following: a. Find the output peak voltage that is used for testing without considering the voltage drop. b. Find the output peak voltage that is used for testing with considering the voltage drop. e. What is the ripple voltage? d. If the lowest capacitor is increased to twice its value, what is the output peak voltage that is used for testing with considering the voltage drop. e. Comparing the results of (b) and (d) above, do you recommend doubling the value of the lowest capacitor or not? f. According to the circuit values, is the 3 stages represents the optimum number of stages for this generator?
1) Calculate the maximum RMS current in p.u. that guarantees the equality of losses between the deformed and non-deformed regime for a power transformer equal to 400 kVA with Pcp = 6% in two cases: a) the transformer feeds a twelve-phase converter Idc=40 A b) the transformer feeds a six-phase converter Idc=40 A.
A generator (480 V, 10 kVA) is connected to an ideal step-up transformer (1:20), and a transmission line (R=20 Ohm and X-60 Ohm), the base values for this system are chosen to be 480 V and 10 kVA at the generator. The line base impedance is: Select one: O a. None of the above O b. 9216 Om O c. 1.25 Ohm O d. 13 Ohm O e. 520 Ohm
A 1200 kVA, 3.3-kV, three-phase, star-connected alternator has an effective resistance that is 1.5 times the dc resistance. The dc resistance is obtained by connecting two terminals to a dc source. The current and voltage are 87.6 A and 6 V, respectively. A field current of 35 A produces a current of 200 A on short-circuit and 1.1 kV on open circuit. Calculate the % change in magnitude of terminal voltage when the full-load of 1200 kVA at 0.9 pf lagging is thrown off.
A 100 kVA, 400 V/250 kV testing transformer has 8% leakage reactance and 2% resistance on 100 kVA base. A cable has to be tested at 500 kV using the above transformer as a resonant transformer at 50 Hz. If the charging current of the cable at 500 kV is 0.4 A, find the series inductance required. Assume 2% resistance for the inductor to be used and the connecting leads. Neglect dielectric loss of the cable. What will be the input voltage to the transformer?
A step-up transformer connected to a 180 V line is used to supply a hydrogen-gas discharge tube with 6.0 kV (rms). The tube dissipates 77 W of power. (a) What is the ratio of the number of turns in the secondary winding to the number of turns in the primary winding? N₂ Np (b) What are the rms currents in the primary and secondary windings (in A)? Ip = Is = A A (c) What is the effective resistance (in 22) seen by the 180 V source? Ω
Electrical engineering A 375 kVA, 6600/400 V, 3-phase core type transformer has a total loss of 3700 watts on full load. The transformer tank is 1.25 m in height and 1 m × 0.5 m in plan. Design a suitable scheme for cooling tubes if the average temperature rise is to be limited to 35 °C. The diameter of the tube is 50 mm and are spaced 75 mm from each other. The average height of the tube is 1.05 m.
A 3-phase, 60 Hz, 2200 V, induction motor develops 500 hp, 0.8 lagging pf and efficiency of 0.94. The power factor is raised to 0.90 lagging by connecting a bank of condensers in delta across the lines. If each of the capacitance unit is built up of four similar 550 V condensers, find the required capacitance of each condenser.
An ideal transformer is rated to deliver 460 kVA at380 V to a customer, as shown in Figure.a. How much current can the transformer supply tothe customer?b. If the customer’s load is purely resistive (i.e., ifpf = 1), what is the maximum power that thecustomer can receive?c. If the customer’s power factor is 0.8 (lagging),what is the maximum usable power the customercan receive?d. What is the maximum power if the pf is 0.7(lagging)?e. If the customer requires 300 kW to operate, what isthe minimum power factor with the given sizetransformer?