If a relay fails to operate for a fault within its reach, it is said to

If a relay fails to operate for a fault within its reach, it is said to
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If a relay fails to operate for a fault within its reach, it is said to Under reach

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Related questions

The relay with inverse time characteristic will operate within?

Last Answer : The relay with inverse time characteristic will operate within 5 to 10 sec.

What are the fault-finding techniques to be used if the equipment fails to operate correctly?

Description : What are the fault-finding techniques to be used if the equipment fails to operate correctly?

Last Answer : 1. Pin point the problem - what is not happening asexpected.2. Read the error messages, error codes if any from theequipment.3. Refer the manual for troubleshooting points follow the stepsprovided.4. Talk to the expert and explain the problem and inform theobserved behavior of the equipment.

What are the fault-finding techniques to be used if the equipment fails to operate correctly?

Description : What are the fault-finding techniques to be used if the equipment fails to operate correctly?

Last Answer : 1. Pin point the problem - what is not happening asexpected.2. Read the error messages, error codes if any from theequipment.3. Refer the manual for troubleshooting points follow the stepsprovided.4. Talk to the expert and explain the problem and inform theobserved behavior of the equipment.

If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug

Description : If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be

Last Answer : If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be 10

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

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

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. 

Which of the following statements is incorrect? (a) Station batteries are used to operate relay only (b) The lightning arresters are basically surge diverters (c) An impedance relay has maximum fault current when fault occurs near the relay (d) A high speed relay has an operation of 1 to 2 cycles

Description : Which of the following statements is incorrect? (a) Station batteries are used to operate relay only (b) The lightning arresters are basically surge diverters (c) An impedance relay has maximum fault current when fault occurs near the relay (d) A high speed relay has an operation of 1 to 2 cycles

Last Answer : (a) Station batteries are used to operate relay only

The relay with inverse time characteristic will operate within (a) 1.5 sec (b) 5 to 10 sec (c) 5 to 20 sec (d) 20 to 30 sec (e) none of the above

Description : The relay with inverse time characteristic will operate within (a) 1.5 sec (b) 5 to 10 sec (c) 5 to 20 sec (d) 20 to 30 sec (e) none of the above

Last Answer : (b) 5 to 10 sec

What happens when the at-fault person fails to respond to the insurance claim lawyers in Wichita, KS?

Description : What happens when the at-fault person fails to respond to the insurance claim lawyers in Wichita, KS?

Last Answer : They would have to mail the as-fault person a letter and so they would comply. And if the do not comply, further legal actions will have to take place.

If the centrifugal switch or relay used for cutting out the starting winding of a split-phase induction motor fails to open once the motor is in operation, the _____________. A. motor will overspeed B. starting winding will burn out C. motor will immediately stall under load D. motor torque will be above normal at rated speed

Description : If the centrifugal switch or relay used for cutting out the starting winding of a split-phase induction motor fails to open once the motor is in operation, the _____________. A. motor will overspeed B ... C. motor will immediately stall under load D. motor torque will be above normal at rated speed

Last Answer : Answer: B

Considering the function of the circuit shown in the illustration, what is the purpose of supplying the thrust lever potentiometers with both (+) and (-) 15 volts? EL-0095 A. To select which lever (bridge or engine room) is active. B. So the circuit can differentiate between ahead and astern commands. C. To provide an alternate voltage supply if the other fails. D. So as to automatically select the position of Relay #

Description : Considering the function of the circuit shown in the illustration, what is the purpose of supplying the thrust lever potentiometers with both (+) and (-) 15 volts? EL-0095 A. To select which ... alternate voltage supply if the other fails. D. So as to automatically select the position of Relay #

Last Answer : Answer: B

If a magnetic controller relay fails to drop out when the coil voltage is removed from the relay, the probable cause may be _____________. A. excessive spring tension B. overvoltage C. excessive current D. welded contacts

Description : If a magnetic controller relay fails to drop out when the coil voltage is removed from the relay, the probable cause may be _____________. A. excessive spring tension B. overvoltage C. excessive current D. welded contacts

Last Answer : Answer: D

Which of the following is/ are the drawbacks of Ring Topology? A) Failure of one computer, can affect the whole network B) Adding or removing the computers disturbs the network activity. C) If the central hub fails, the whole network fails to operate. D) Both of A and B

Description : Which of the following is/ are the drawbacks of Ring Topology? A) Failure of one computer, can affect the whole network B) Adding or removing the computers disturbs the network activity. C) If the central hub fails, the whole network fails to operate. D) Both of A and B

Last Answer : D) Both of A and B

What is the function of watchdog timer? a) The watchdog Timer is an external timer that resets the system if the software fails to operate properly. b) The watchdog Timer is an internal timer that sets the system if the software fails to operate properly. c) The watchdog Timer is an internal timer that resets the system if the software fails to operate properly. d) None of them

Description : What is the function of watchdog timer? a) The watchdog Timer is an external timer that resets the system if the software fails to operate properly. b) The watchdog Timer is an internal timer ... internal timer that resets the system if the software fails to operate properly. d) None of them

Last Answer : b) The watchdog Timer is an internal timer that sets the system if the software fails to operate properly.

What is the function of watchdog timer? a) The watchdog Timer is an external timer that resets the system if the software fails to operate properly. b) The watchdog Timer is an internal timer that sets the system if the software fails to operate properly. c) The watchdog Timer is an internal timer that resets the system if the software fails to operate properly. d) None of them

Description : What is the function of watchdog timer? a) The watchdog Timer is an external timer that resets the system if the software fails to operate properly. b) The watchdog Timer is an internal timer ... internal timer that resets the system if the software fails to operate properly. d) None of them

Last Answer : c) The watchdog Timer is an internal timer that resets the system if the software fails to operate properly.

Which of the following is/ are the drawbacks of Ring Topology? A) Failure of one computer, can affect the whole network B) Adding or removing the computers disturbs the network activity. C) If the central hub fails, the whole network fails to operate. D) Both of A and B

Description : Which of the following is/ are the drawbacks of Ring Topology? A) Failure of one computer, can affect the whole network B) Adding or removing the computers disturbs the network activity. C) If the central hub fails, the whole network fails to operate. D) Both of A and B

Last Answer : D) Both of A and B

Which of the following is/ are the drawbacks of Ring Topology? A) Failure of one computer, can affect the whole network B) Adding or removing the computers disturbs the network activity. C) If the central hub fails, the whole network fails to operate. D) Both of A and B

Description : Which of the following is/ are the drawbacks of Ring Topology? A) Failure of one computer, can affect the whole network B) Adding or removing the computers disturbs the network activity. C) If the central hub fails, the whole network fails to operate. D) Both of A and B

Last Answer : D) Both of A and B

Explain fault bus protection scheme.

Description : Explain fault bus protection scheme.

Last Answer : Fault bus protection of busbar: In this scheme, the substation is so designed that every fault on the bus bar is converted to earth fault. Under normal operating conditions, there is no current flowing ... This results in operation of relay to actuate trip coil of CB to trip the circuit.

How the alternator can be protected from inter-turn fault?

Description : How the alternator can be protected from inter-turn fault?

Last Answer : Inter-turn fault Protection: Figure shows scheme for one phase only. It is identical for other phases. Under normal working condition, the two currents in the stator winding sections (S1 and S2) are ... relay coil to operate it, leading to isolation of the alternator from the power system.

If the % reactance upto the fault point is 20%, then the short circuit current will be

Description : If the % reactance upto the fault point is 20%, then the short circuit current will be

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With fault clearing time, the transient stability of a power system

Description : With fault clearing time, the transient stability of a power system

Last Answer : With fault clearing time, the transient stability of a power system decreases

To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ?

Description : To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ?

Last Answer : To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ? Δ-Δ connection

The inverse definite mean time relays are used for over current and earth fault protection of transformer against?

Last Answer : The inverse definite mean time relays are used for over current and earth fault protection of transformer against internal short-circuits.

Fault diverters are basically?

Last Answer : Fault diverters are basically fast switches.

In which fault the maximum short circuit current occurs?

Description : In which fault the maximum short circuit current occurs?

Last Answer : In three phase bolted fault the maximum short circuit occurs.

Which is the most common type of fault?

Description : Which is the most common type of fault?

Last Answer : Single phase to ground fault is the most common type of fault.

With the help of neat diagram, explain operation of static relay.

Description : With the help of neat diagram, explain operation of static relay.

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Describe the construction and Operation of Buchholz relay with neat labeled diagram.

Description : Describe the construction and Operation of Buchholz relay with neat labeled diagram.

Last Answer : Construction of Buchholz Relay: It takes the form of a domed vessel placed in the connecting pipe between the main tank and the conservator. The device has two elements. The upper element ... manner that it senses the sudden violent movement of oil/gas from transformer tank to conservator. 

Describe the operation of current differential relay with neat sketch.

Description : Describe the operation of current differential relay with neat sketch.

Last Answer : Operation of Current Differential Relay: Figure shows an arrangement of an overcurrent relay connected to operate as a differential relay for alternator protection under fault conditon. ... current flows through relay coil, causing relay to operate for protection of alternator winding.

With a neat sketch, explain the working of Thermal relay.

Description : With a neat sketch, explain the working of Thermal relay.

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Define the following terms with respect to protective relays i) Relay time ii) Reset current iii) Plug setting multiplier and iv) Time setting multiplier

Description : Define the following terms with respect to protective relays i) Relay time ii) Reset current iii) Plug setting multiplier and iv) Time setting multiplier

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Draw a typical time-current characteristic for IDMT relay.

Description : Draw a typical time-current characteristic for IDMT relay. 

Last Answer : Time-Current Characteristic for IDMT Relay:

Explain operation of balanced beam type relay.

Description : Explain operation of balanced beam type relay.

Last Answer : Balanced Beam Type Relay: Under normal operating condition the current through relay coil is such that the beam is held in the horizontal position by the spring. When the fault occurs on the system the ... becomes greater than pick-up value and beam is attracted to close the trip circuit. 

Explain Buchholz relay with neat labelled diagram.

Description : Explain Buchholz relay with neat labelled diagram.

Last Answer : Buchholz relay: The relay is located in the path of the oil from transformer tank to conservator. As seen from diagram, the upper mercury switch operates the alarm circuit due to tilting of the ... manner that it senses the sudden violent movement of oil from transformer tank to conservator.

Explain MHO relay in detail.

Description : Explain MHO relay in detail.

Last Answer : MHO Relay: In this relay, poles 1, 2, 3 are energized by a voltage V through polarizing coil to produce flux, the capacitor connected provides phase shift. The left pole 4 is energized by a current which is the ... hence on the ratio (I/V) = Y i.e. admittance, hence called as MHO relay.

Describe over current relay with time-current characteristic.

Description : Describe over current relay with time-current characteristic.

Last Answer : Over current relay with time-current characteristics:- 1. Definite time over current relay: Operating time is constant, the relays operates after a predetermined time when the current exceeds the pickup ... of fault current and definite time characteristics at higher values of fault current.

Explain operation of µP based relay with block diagram

Description : Explain operation of µP based relay with block diagram

Last Answer : Operation of Microprocessor (µP) based relay: The inputs from the power system through CTs and PTS are received by the analog Input receiver; they are sampled simultaneously or ... compares the dynamic inputs and decides accordingly to generate trip/alarm signal to the output device.

Explain construction and operation of induction type directional over current relay.

Description : Explain construction and operation of induction type directional over current relay.

Last Answer : Directional overcurrent relay: Construction: It consists of two units: i) Non-directional Over-current unit ii) Directional power unit The directional unit consists of upper electromagnet ... closes the trip circuit. This operates circuit breaker which isolates the faulty section. 

The reactance relay is essentially:

Description : The reactance relay is essentially: A) an over-voltage relay with current restraint B) an over-voltage relay with directional restraint C) a directional relay with voltage restraint D) a directional relay with current restraint 

Last Answer : an over voltage relay with delay an over voltage relay with directional resistance

The operation of the relay which is most affected due to arc resistance is

Description : The operation of the relay which is most affected due to arc resistance is A) Mho relay B) Reactance relay C) Impedance relay D) All are equally affected

Last Answer : The operation of the relay which is most affected due to arc resistance is Mho relay

The most efficient torque — producing actuating structure for induction — type relay is:

Description : The most efficient torque — producing actuating structure for induction — type relay is:

Last Answer : The most efficient torque — producing actuating structure for induction — type relay is: induction-cup structure

In a biased differential relay, the bias is defined as the ratio of

Description : In a biased differential relay, the bias is defined as the ratio of  A) Number of turns of restraining coil and operating coil B) Operating coil current and restraining coil current C) Faulteurrent and operating coil current D) Fault current and restraining coil current

Last Answer : In a biased differential relay, the bias is defined as the ratio of Number of turns of restraining coil and operating coil 

30°, 60° and 90° connections are made in a directional relay to render the relay

Description : 30°, 60° and 90° connections are made in a directional relay to render the relay (A) Sufficient torque under fault conditions (B) Zero torque under fault conditions (C) Current grading (D) Time grading

Last Answer : 30°, 60° and 90° connections are made in a directional relay to render the relay Sufficient torque under fault conditions

Which relay is more sensitive ? 1 VA or 2 VA ?

Description : Which relay is more sensitive ? 1 VA or 2 VA ? (A) 1 VA (B) 2 VA (C) Both are equally sensitive (D) Both are insensitive

Last Answer : Which relay is more sensitive ? 1 VA or 2 VA ? (A) 1 VA (B) 2 VA (C) Both are equally sensitive (D) Both are insensitive

The purpose of the restraining coil in a biased differential relay is

Description : The purpose of the restraining coil in a biased differential relay is  (A) To reduce CT saturation during fault.  (B) To increase the sensitivity of the relay.  (C) To match the transformation ratio.  (D) To limit the spill current through the relay during heavy external fault.

Last Answer : d

A relay used for protection of motors against overload is :

Description : A relay used for protection of motors against overload is :  (A) Impedance relay (B) Electromagnetic attraction type (C) Thermal relay (D) Buchholz's relay

Last Answer : D

A relay has a rating of 5 A, 2.2 sec IDMT and a relay setting of 125% TMS = 0.6. It is connected to a supply

Description : A relay has a rating of 5 A, 2.2 sec IDMT and a relay setting of 125% TMS = 0.6. It is connected to a supply circuit through a C.T. 400/5 ratio. The fault current is 4000 A. The operating current of the relay is

Last Answer : A relay has a rating of 5 A, 2.2 sec IDMT and a relay setting of 125% TMS = 0.6. It is connected to a supply circuit through a C.T. 400/5 ratio. The fault current is 4000 A. The operating current of the relay is 6.25A

The operating time of instantaneous relay is

Description : The operating time of instantaneous relay is

Last Answer : The operating time of instantaneous relay is 0.1 sec

What is the difference between relay and contactor?

Description : What is the difference between relay and contactor?

Last Answer : Relay have smaller ratings. Contactor is a high rating relay.

A negative sequence relay is used for protection of

Description : A negative sequence relay is used for protection of  (1) Generator (3) Motor (2) Transformer (4) Long Transmission lines

Last Answer : A negative sequence relay is used for protection of Generator