Adjustment resistance in rotor system will --------when three phase load decrease. remain constant not change decrease Increase What will happen if a stationary alternator (off) is connected to a live power system? It will decrease bus bar voltage It will get short circuited It is likely to run as a synchronous motor It will disturb generated e.m.f. of other paralleled alternators. Division: *

Adjustment resistance in rotor system will --------when three phase load decrease. remain constant not change decrease Increase What will happen if a stationary alternator (off) is connected to a live power system? It will decrease bus bar voltage It will get short circuited It is likely to run as a synchronous motor It will disturb generated e.m.f. of other paralleled alternators. Division: *

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

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.56P: Three single-phase two-winding transformers, each rated 3kVA,220/110volts,60Hz, with a 0.10 per-unit...

See similar textbooks

Similar questions

A short shunt compound generator has an armature, shunt field and series fieldresistances of 0.02 ohm, 80 ohm and 0.03 ohm respectively. The generator’s induced emfis 510V when the terminal voltage is 500V. How much load current is delivered underthis condition? Answer: 197.47A
A three-phase, 250 MVA, 16 kV rated synchronous generator is feeding into an infinite bus bar at 15 kV. The generator has a synchronous reactance of 1.62 pu. It is found that the machine excitation and mechanical power input are adjusted to give E = 24 kV and power angle δ = 30◦. a) Determine the line current and active and reactive power fed to the generator terminal. b) With reference to part (a) current is to be reduced by 20% at the same power factor by adjusting mechanical power input to the generator and its excitation. Determine E, angle δ and mechanical power input. c) With the reduced current as in part (c), the power is to be delivered to generator terminal at unity power factor, what are the corresponding values of E and δ and also the mechanical power input to the generator. Per-unit values are given on machine rating as the base.
say the secondary windings are connected in series instead of parallel, that is, terminal 8 is connected to terminal 9, and terminal 10 is connected to terminal 11. What would be the ac voltage in volts between terminals 7 & 12? Assume load is not connected.
2- Why it's imporctical carry out actual load test on large rating transformers ?3- What will be the current in the primary windings?i) When secondaries are not loaded ?ii) When secondaries are loaded ?
Three zones of a single-phase circuit are identified in the figure with a generator voltage specification of 240 V. The zones are connected by the transformers T1 and T2, whose ratings are shown below.Using base values of 30 kVA and 240 volts in zone 1, draw the pu circuit and determine the pu impedance and pu source voltage. Then calculate the load current in pu and in amperes.*Round the final answer to four decimal places, polar form, and label it with the correct units.
1. What are the reasons of drop of terminal voltage due to load in alternator? 2. Why synchronous impedance method does not provide the exact value of
A (500 MW) generator is delivering (180 MW) to infinite bus through the unit transformer and double transmission lines. The per-unit ractances for a given system are shown in figure below andall the reactances are based on (100 MW) base. The generator emf is ( 1.35p .u.). Determine whether the system remains stable after one circuit of the lines is switch off?
A three-phase, 250 MVA, 16 kV rated synchronous generator is feeding into an infinite bus bar at 15 kV. The generator has a synchronous reactance of 1.62 pu. It is found that the machine excitation and mechanical power input are adjusted to give E = 24 kV and power angle δ = 30◦. a) Determine the line current and active and reactive power fed to the generator terminal. b) The mechanical power input to the generator is increased by 20% from that in part (a) but its excitation is not changed. Find the new line current and power factor. c) With reference to part (a) current is to be reduced by 20% at the same power factor by adjusting mechanical power input to the generator and its excitation. Determine E, angle δand mechanical power input.
A three phase synchronous generator with negligible resistance and Xs=20 ohm has induced voltage as well as terminal voltage per phase equal to 230 V. for the load angle of 30o, power received by the bus is .........W.
-The sum of the armature reactance and.............reactance is the reactance of the synchronous generator after the short circuit fault is cleared. -The selection of number of generating sources to meet the expected load is called as economic dispatch. Select one: True False
1) A 50 Hz, 3.75 MVA, 3.18 kV, three-phase synchronous generator with rated (nominal) currentof In = 682 A has open- and short-circuit characteristic listed in Table 1 and Table 2 respectively.Determine saturated and unsaturated synchronous reactance in per-unit and in Ohms and calulateshort circuit ratio (SCR). The generator is delivering rated power at 0.95 power factor leading atthe rated therminal voltage. Using given open-circuit characteristic approximately determine thefield current under rated loading.
Problem 2 Two shunt generators A and B operate in parallel and their load characteristics maybe taken as straight lines. The voltage falls from 240V at no load to 200V at200A, while that of B falls from 245V at no load to 220V at 150A. Determine the bus bar voltage when supplying 66.9KW load. How is the load divided between two generators?