In which type of fault all 3-phase components are equal a) L-G b) L-L c) L-L-G d) 3-Phase fault

In which type of fault all 3-phase components are equal
a) L-G
b) L-L
c) L-L-G
d) 3-Phase fault
by

1 Answer

Answer :

Ans: 3-Phase fault
by

Related questions

Which of the following are the components of loamy soils? 1. Red soil 2. Clay soil 3. Alluvial soil 4. Silt soil 5. Sandy soil In d i a n So i l , Se a s o n s a n d N a t u r a l Ve g e t a t i o n (a) I and II (b) I, III and IV (c) II and V (d) II, III and V

Description : Which of the following are the components of loamy soils? 1. Red soil 2. Clay soil 3. Alluvial soil 4. Silt soil 5. Sandy soil In d i a n So i l , Se a s o n s a n d N a t u r a l Ve g e t a t i o n (a) I and II (b) I, III and IV (c) II and V (d) II, III and V

Last Answer : Ans: (c)

As shown in the illustration, what maintenance would be required of the circuit components? EL-0058 A. Change out both 'C' units monthly. B. Clean the glass surrounding 'E1' & 'E2' as needed. C. File the points at the upper end of 'G' every six months. D. Take megger readings on 'E1' & 'E2' windings quarterly.

Description : As shown in the illustration, what maintenance would be required of the circuit components? EL-0058 A. Change out both 'C' units monthly. B. Clean the glass surrounding 'E1' & 'E2' as needed. C. File ... upper end of 'G' every six months. D. Take megger readings on 'E1' & 'E2' windings quarterly.

Last Answer : Answer: B

Which two components, shown in the illustration, acting together will disconnect the motor from the line in case of a sustained motor overload? EL-0080 A. 'G' and 'H' B. 'E' and 'I' C. 'F' and 'H' D. 'E' and 'G'

Description : Which two components, shown in the illustration, acting together will disconnect the motor from the line in case of a sustained motor overload? EL-0080 A. 'G' and 'H' B. 'E' and 'I' C. 'F' and 'H' D. 'E' and 'G'

Last Answer : Answer: B

Write the symmetrical components of three phase system.

Description : Write the symmetrical components of three phase system.

Last Answer : 1.positive sequence components 3. negative sequence components. 4. zero sequence components.

The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are: (A) 1 (B) 2 (C) 3 (D) 0

Description : The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are: (A) 1 (B) 2 (C) 3 (D) 0

Last Answer : (B) 2

relay is preferred for phase fault on short transmission line. (a) Induction type (b) Reactance (c) Impedance (d) None of the above

Description : relay is preferred for phase fault on short transmission line. (a) Induction type (b) Reactance (c) Impedance (d) None of the above

Last Answer : (b) Reactance

Purpose of Over current & earth fault relay; type- CAG

Description : Purpose of Over current & earth fault relay; type- CAG  

Last Answer : This relays are designed for instantaneous phase or earth fault protection and instantaneous high set over current protection.; A standard hinged-armature unit forms the basic movement for this relay. It consists an ... to the end of the core while the other arm to operate a set of contacts.  

Purpose of Directional inverse Over current & earth fault relay; type- CDD

Description : Purpose of Directional inverse Over current & earth fault relay; type- CDD

Last Answer : Directional phase or earth fault protection of ring-mains, parallel transformers, transformer feeders, parallel feeders etc., employing the time graded principle.; This relay comprises an inductive ... induction disc unit. The directional unit is normally provided with voltage polarising coils. 

The necessary condition for phase equilibrium in a multiphase system of N components is that the (A) Chemical potentials of a given component should be equal in all phases (B) Chemical potentials of all components should be same in a particular phase (C) Sum of the chemical potentials of any given component in all the phases should be the same (D) None of these

Description : The necessary condition for phase equilibrium in a multiphase system of N components is that the (A) Chemical potentials of a given component should be equal in all phases (B) Chemical potentials of all ... potentials of any given component in all the phases should be the same (D) None of these

Last Answer : (A) Chemical potentials of a given component should be equal in all phases

As shown in the illustration, the motor generator(M-G) set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Description : As shown in the illustration, the motor generator(M-G) set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Last Answer : Answer: C

As shown in the illustration, the M-G set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Description : As shown in the illustration, the M-G set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Last Answer : Answer: C

Ungrounded neutral transmission system is not recommended because of system (a) insulation being overstressed due to over voltages (b) insulation overstress may lead to failure and subsequent phase to phase faults (c) being inadequately protected against ground fault (d) all of the above

Description : Ungrounded neutral transmission system is not recommended because of system (a) insulation being overstressed due to over voltages (b) insulation overstress may lead to failure and subsequent phase to phase faults (c) being inadequately protected against ground fault (d) all of the above

Last Answer : (d) all of the above

at the terminal of a three-phase 6.6Kv alternator a load R=200 ohm is connected between two-phase and the third phase is opened. Z1=z2=5 ohm Zo=2 find out the fault current .

Description : at the terminal of a three-phase 6.6Kv alternator a load R=200 ohm is connected between two-phase and the third phase is opened. Z1=z2=5 ohm Zo=2 find out the fault current .

Last Answer : 32A

Electrical fault between two windings of same phase of a generator having double star winding can be

Description : Electrical fault between two windings of same phase of a generator having double star winding can be detected by the following protection in a generator:

Last Answer : Electrical fault between two windings of same phase of a generator having double star winding can be detected by the following protection in a generator: inter turn fault protection

The steady-state fault current during a 3 phase terminal fault on a generator is limited by:

Description : The steady-state fault current during a 3 phase terminal fault on a generator is limited by: (1) Transient reactance of the generator (2) Sub-transient reactance of the generator (3) Synchronous reactance of the generator (4) DC off—set during the instant of the fault

Last Answer : 1

In case of a 3-phase short-circuit fault in a system, the power fed into the system is

Description : In case of a 3-phase short-circuit fault in a system, the power fed into the system is   (a) Mostly reactive (b) Reactive only (c) Mostly active (d) Active and Reactive both equal 

Last Answer : In case of a 3-phase short-circuit fault in a system, the power fed into the system is Mostly reactive 

Which relay is preferred for phase fault on short transmission line?

Last Answer : Reactance relay is preferred for phase fault on short transmission line.

When earth fault occurs: a) voltage potential at the earth mat increases due to grounding b) voltage potential at the earth mat decreases due to grounding c) voltage potential at the earth mat remains zero irrespective of fault d) none of the above

Description : When earth fault occurs: a) voltage potential at the earth mat increases due to grounding b) voltage potential at the earth mat decreases due to grounding c) voltage potential at the earth mat remains zero irrespective of fault d) none of the above

Last Answer : Ans: A

Moisture absorbed in the windings or condensed on the surface of electrical machinery insulation ________. A. is good for long term preserving since most insulation is organic and contains some amount B. lowers the insulation value and is a common cause of fault grounds in idle machines C. will enhance insulation resistance only if it is fresh water and contains no salt D. reduces the amount of current supplied or drawn by the machine so horsepower is limited

Description : Moisture absorbed in the windings or condensed on the surface of electrical machinery insulation ________. A. is good for long term preserving since most insulation is organic and contains some amount B. ... D. reduces the amount of current supplied or drawn by the machine so horsepower is limited

Last Answer : Answer: B

When a console indicating lamp burns out, attempts to renew it should not be made while maneuvering because _______________. A. the new lamp may be of a higher wattage and cause heat damage to the lens B. removing a faulty lamp usually causes an alarm to sound on the bridge C. attention should be paid only to engine orders D. a socket/wiring fault may cause a ground or short circuit to shut down a vital function

Description : When a console indicating lamp burns out, attempts to renew it should not be made while maneuvering because _______________. A. the new lamp may be of a higher wattage and cause heat damage to the lens ... D. a socket/wiring fault may cause a ground or short circuit to shut down a vital function

Last Answer : Answer: D

An open-circuit fault between the pressure switch and the 'annunciator module' shown in the illustration would cause the alarm circuit to react in the same manner as if ___________. EL-0094 A. 3.5 volts were applied to the 'setpoint module' B. 'reduction gear lube oil pressure' fell below switch setting C. 50 PSI were applied to the 'setpoint module' D. the pressure switch closed

Description : An open-circuit fault between the pressure switch and the 'annunciator module' shown in the illustration would cause the alarm circuit to react in the same manner as if ___________. EL-0094 A. 3.5 ... below switch setting C. 50 PSI were applied to the 'setpoint module' D. the pressure switch closed

Last Answer : Answer: B

Action carried out by the relay and circuit breaker during fault condition?

Description : Action carried out by the relay and circuit breaker during fault condition?

Last Answer : Answer: After the relay sensing the fault condition, relay operates and close the trip coils. The effect of this will be circuit breaker operate to open the contacts.

State the significance of double line fault.

Description : State the significance of double line fault.

Last Answer : It has no zero sequence component and the positive and negative sequence networks are connected in parallel.

State the significance of single line to ground fault.

Description : State the significance of single line to ground fault.

Last Answer : In single line to ground fault all the sequence networks are connected in series. All the sequence currents are equal and the fault current magnitude is three times its sequence currents.

What is meant by fault calculations

Description : What is meant by fault calculations

Last Answer : The fault condition of a power system can be dived into subtransient, transient and steady state periods. The currents in the various parts of the system and in the fault are different in ... for various types of faults at various locations in the system are commenly reffered as fault calculations.

What is symmetrical and unsymmetrical fault?

Description : What is symmetrical and unsymmetrical fault?

Last Answer : The fault is called symmetrical fault if the fault current is equal in all the phases. The fault is called unsymmetrical fault if the fault current is not equal in all the phases.

List the various types of series and shunt fault?

Description : List the various types of series and shunt fault?

Last Answer : Shunt faults are, Line to ground fault line to line fault, double line to ground fault, three phase fault. Series faults are, One open conductor fault Two open conductor fault

Why fault accurs in a power system?

Description : Why fault accurs in a power system?

Last Answer : The fault occur in a power system due to insulation failure of equipments, flashover of lines initiated by a lightning stroke, due to permanent damage to conductors and towers

What is meant by a fault?

Description : What is meant by a fault?

Last Answer : A fault in a circuit is any failure which interferes with the normal flow of current. The faults are associated with abnormal change in current, voltage and frequency of the power systwm. The faults may ... to sence the faults to isolate the faulty part from the healthy part in the event of fault.

For a fault in switchyard lightning arrestor, what protection will act?

Description : For a fault in switchyard lightning arrestor, what protection will act?

Last Answer : Bus bar differential protection.  

Why core balance CT is preferred over residual connected CT’s to sense earth fault in 6.6 kV feeders?

Description : Why core balance CT is preferred over residual connected CT’s to sense earth fault in 6.6 kV feeders?

Last Answer : a) To avoid relay mal-operation due to CT saturation b) Better sensitivity is got. c) High pickup and TMS avoided in IDMT earth fault relay. 

Why 2 types of earth fault relays in 6.6 kV side of transformers?

Description : Why 2 types of earth fault relays in 6.6 kV side of transformers?

Last Answer : I – Trips 6.6 kV breakers only. It gives primary protection for 6.6 kV bus bars. I1 – Trips the both HT and LT breakers. It acts as a backup to ref and also acts as backup to bus bar earthfault relay. 

Why in transformer the LV CB also be tripped along with HV CB for a primary side fault?

Description : Why in transformer the LV CB also be tripped along with HV CB for a primary side fault?

Last Answer : Auxiliary transformer 415v delta star transformer, if HV CB alone tripped then back feeding from LV side (say DG runs parallel with transformer)—arcing voltage at the fault on primary—fault fed for more time – more damage.  

How generator earth fault relay works?

Description : How generator earth fault relay works? 

Last Answer : 100% earth fault relay works on the principle involving monitoring of neutral side and line side components of 3rd harmonic voltages produced by generator in service. Since the machine is grounded with ... be detected by VL3 neutral displacement module, which is tuned to find frequency.   

Where fault level is more, whether in generator bus duct or UT bus duct? Why?

Description : Where fault level is more, whether in generator bus duct or UT bus duct? Why?

Last Answer : Fault level is more in UT bus duct. Because the fault currents fed by the both generator and GT adds up within UT bus duct in case there is a fault in UT bus duct. 

Will rotor earth fault relay operate for earth fault in main exciter winding or RCU Diode Bridge also?

Description : Will rotor earth fault relay operate for earth fault in main exciter winding or RCU Diode Bridge also? 

Last Answer : Yes. 

Why not high resistance for earth fault than using grounding transformer & resistor 0.45 ohms?

Description : Why not high resistance for earth fault than using grounding transformer & resistor 0.45 ohms?

Last Answer : It is mechanically unwide. Difficult to manufacture.  

Why earth fault current of generator should not be reduced below 5A?

Description : Why earth fault current of generator should not be reduced below 5A? 

Last Answer : To limit over voltage due to neutral shift.  

The illustrated circuit is a wheatstone bridge. If the meter 'G' reads 0 with the switch closed then ________. EL-0024 A. the current through R1 - R2 is equal to the current through R3 - Rx B. the voltage across b - d is equal to the voltage of E C. the resistance of Rx is equal to the resistance of R2 D. all the above are true

Description : The illustrated circuit is a wheatstone bridge. If the meter 'G' reads 0 with the switch closed then ________. EL-0024 A. the current through R1 - R2 is equal to the current through R3 - Rx B. the voltage ... of E C. the resistance of Rx is equal to the resistance of R2 D. all the above are true

Last Answer : Answer: A

Which of the following statements is incorrect ? (a) Lightning arrestors are used before the switchgear (b) Shunt reactors are used as compensation reactors (c) The peak short current is (1.8 xV2) times the A.C. component (d) The MVA at fault is equal to base MVA divided by per unit equivalent fault reactance

Description : Which of the following statements is incorrect ? (a) Lightning arrestors are used before the switchgear (b) Shunt reactors are used as compensation reactors (c) The peak short current is (1.8 xV2) ... component (d) The MVA at fault is equal to base MVA divided by per unit equivalent fault reactance

Last Answer : (a) Lightning arrestors are used before the switchgear

A power system is subjected to a fault which makes the zero sequence component of current equal to zero

Description :  A power system is subjected to a fault which makes the zero sequence component of current equal to zero. The nature of fault current is: A) Double line to ground fault B) Line to line fault C) Line to ground fault D) Three-phase to ground fault

Last Answer :  A power system is subjected to a fault which makes the zero sequence component of current equal to zero. The nature of fault current is: Line to line fault

In a three-phase electrical system, three ground detecting lamps are provided. One lamp goes dark and the others increase in brightness. When the test button is pushed, all lamps have equal illumination. You should conclude that ____________. A. there is a ground on the line with the dark lamp B. the dark lamp must be replaced C. there are grounds on the lines with the bright lamps D. this is a normal condition

Description : In a three-phase electrical system, three ground detecting lamps are provided. One lamp goes dark and the others increase in brightness. When the test button is pushed, all lamps have equal illumination. You ... C. there are grounds on the lines with the bright lamps D. this is a normal condition

Last Answer : Answer: A

The circuit illustrated represents a single phase AC ground detecting system. If a ground occurs on line 'B', which of the lamps will burn the brightest? EL-0008 A. X B. Y C. Both will be equal brightness. D. both will go out.

Description : The circuit illustrated represents a single phase AC ground detecting system. If a ground occurs on line 'B', which of the lamps will burn the brightest? EL-0008 A. X B. Y C. Both will be equal brightness. D. both will go out.

Last Answer : Answer: A

For the illustrated wiring of a three phase alternator, which statement is true about the current? EL-0074 A. phase current is 1.73 times the line current B. line current is 1.73 times the phase current C. there is no relationship between phase current and line current D. line current is equal to phase current

Description : For the illustrated wiring of a three phase alternator, which statement is true about the current? EL-0074 A. phase current is 1.73 times the line current B. line current is 1.73 times the ... . there is no relationship between phase current and line current D. line current is equal to phase current

Last Answer : Answer: D

In the illustrated three phase alternator, line voltage is _________. EL-0074 A. 1.73 times the phase voltage B. equal to the phase voltage C. phase voltage divided by 1.73 D. unable to answer this question without knowing the line current

Description : In the illustrated three phase alternator, line voltage is _________. EL-0074 A. 1.73 times the phase voltage B. equal to the phase voltage C. phase voltage divided by 1.73 D. unable to answer this question without knowing the line current

Last Answer : Answer: A

In a three-phase, open-delta connected transformer, the line current is equal to _____________. A. the phase current B. three times the phase current C. the sum of any two phase currents D. the difference of any two phase currents

Description : In a three-phase, open-delta connected transformer, the line current is equal to _____________. A. the phase current B. three times the phase current C. the sum of any two phase currents D. the difference of any two phase currents

Last Answer : Answer: A

One important difference between wye-connected and delta-connected generators is that delta connections have ____________. A. line voltages equal to the vector sum of the phase voltages B. phase voltages 90° out of sync C. line current equal to the phase current D. line voltage equal to the phase voltage

Description : One important difference between wye-connected and delta-connected generators is that delta connections have ____________. A. line voltages equal to the vector sum of the phase voltages B. phase voltages 90° ... C. line current equal to the phase current D. line voltage equal to the phase voltage

Last Answer : Answer: D

Which type of flux should be used when soldering electrical wire connections and electronic components? A. Silver flux B. Rosin flux C. Solid flux D. Acid flux

Description : Which type of flux should be used when soldering electrical wire connections and electronic components? A. Silver flux B. Rosin flux C. Solid flux D. Acid flux

Last Answer : Answer: B