A three-phase star-connected alternator is rated at 1750 KVA, 13.8 KV, The armature resistance and synchronous reactance are 1.2 Ω and 25 Ω per phase respectively. Calculate the percentage regulation for a load of a) 45% load at 0.9 power factor lagging. b) 65% load at 0.75 power factor leading.

A three-phase star-connected alternator is rated at 1750 KVA, 13.8 KV, The armature resistance and synchronous reactance are 1.2 Ω and 25 Ω per phase respectively. Calculate the percentage regulation for a load of a) 45% load at 0.9 power factor lagging. b) 65% load at 0.75 power factor leading.

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 2.41P

See similar textbooks

Similar questions

The total instantaneous power absorbed by a three-phase motor (under balanced steady-state conditions) as well as a balanced three-phase impedance load is (a) A constant (b) A function of time
While the instantaneous electric power delivered by a single-phase generator under balanced steady-state conditions is a function of time havi ng two components of a constant and a double-frequency sinusoid, the total instantaneous electric power delivered by a three-phase generator under balanced steady-state conditions is a constant. (a) True (b) False
A single-phase 100-kVA,2400/240-volt,60-Hz distribution transformer is used as a step-down transformer. The load, which is connected to the 240-volt secondary winding, absorbs 60 kVA at 0.8 power factor lagging and is at 230 volts. Assuming an ideal transformer, calculate the following: (a) primary voltage, (b) load impedance, (c) load impedance referred to the primary, and (d) the real and reactive power supplied to the primary winding.
The total instantaneous power delivered by a three-phase generator under balanced operating conditions is (a) A function of time (b) A constant
An industrial plant consisting primarily of induction motor loads absorbs 500 kW at 0.6 power factor lagging. (a) Compute the required kVA rating of a shunt capacitor to improve the power factor to 0.9 lagging. (b) Calculate the resulting power factor if a synchronous motor rated at 500 hp with 90 efficiency operating at rated load and at unity power factor is added to the plant instead of the capacitor. Assume constant voltage (1hp=0.746kW).
A single-phase, 120V(rms),60Hz source supplies power to a series R-L circuit consisting of R=10 and L=40mH. (a) Determine the power factor of the circuit and state whether it is lagging or leading. (b) Determine the real and reactive power absorbed by the load. (c) Calculate the peak magnetic energy Wint stored in the inductor by using the expression Wint=L(Irms)2 and check whether the reactive power Q=Wint is satisfied. (Note: The instantaneous magnetic energy storage fluctuates between zero and the peak energy. This energy must be sent twice each cycle to the load from the source by means of reactive power flows.)
An infinite bus, which is a constant voltage source, is connected to the primary of the three-winding transformer of Problem 3.53. A 7.5-MVA,13.2-kV synchronous motor with a sub transient reactance of 0.2 per unit is connected to the transformer secondary. A5-MW,2.3-kV three-phase resistive load is connected to the tertiary Choosing a base of 66 kV and 15 MVA in the primary, draw the impedance diagram of the system showing per-unit impedances. Neglect transformer exciting current, phase shifts, and all resistances except the resistive load.
A 6,600V, 1,200 kVA, 3-phase alternator is delivering full load at 0.80 power factor lagging. Its reactance is 25% and resistance is negligible. By changing its excitation, the emf is increased by 30%. At this load, determine the new current and power factor. Draw the single line diagram.
A 3-phase ,13500V, star connected alternator is rated at 1600kVA. The armature effective resistance and synchronous reactance are 1.5 ohm and 30 ohm respectively per phase. Calculate the percentage regulation for a load of 1280kW at 0.8 power factor lagging
A 15kVA, 440V, single-phase alternator draws a field current of 5A at rated load. With the same field current, the open circuit emf and short-circuit current are 100V and 80A respectively. The ohmic resistance of the armature between terminals is 0.12 ohm. The ratio of effective to ohmic resistance maybe taken as 1.1. Determine the voltage regulation (in %) when the load is purely resistive.
A 30 MVA, three-phase, wye-connected, 60 Hz, 13.8 kV synchronous alternator has negligible stator resistance and synchronous reactance of 10 W/phase. Calculate the % voltage regulation of the alternator when it is operation in isolation (stand-alone) and delivering rated MVA to a 0.866 pf leading load at 13.8 kV. Calculate the % voltage regulation of the alternator when it is operation in isolation (stand-alone) and delivering rated MVA to a 0.707 pf lagging load at 13.8 kV.
A 1200 kVA, 6600 volts, 3-phase Y connected alternator, has an effective resistance of 0.4 ohms and a synchronous reactance of 6 ohms per phase. It delivers full load current at 0.8 lagging power factor at rated voltage. What will be the generated voltage if the power factor is change to 0.8 leading. Solve for the % voltage regulation both for 0.8 lagging and 0.8 leading power factors.