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

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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1 Answer

Answer :

1) Relay Time: The time interval between occurrence of fault and closure of relay contacts. 

2) Reset Current: The value of current below which the relay resets and comes back to its original state is called as reset current. 

3) Plug Setting Multiplier: It is the ratio of fault current in relay coil to pick-up current. 

 OR 

 PSM = ( Fault current in relay coil) / ( Pickup current) 

4) Time Setting Multiplier: The adjustment arrangement provided for setting the operation time of relay is known as Time setting multiplier. 
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Related questions

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If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be

Description : If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be

Last Answer : If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be 10 A

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

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Protective relays are devices that detect abnormal conditions in electrical circuits by measuring?

Last Answer : Protective relays are devices that detect abnormal conditions in electrical circuits by measuring constantly the electrical quantities which differ during normal and abnormal conditions.

Plug Setting Multiplier (PSM) is the ratio of

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Description : Protective relays are devices that detect abnormal conditions in electrical circuits by measuring (a) current during abnormal condition (b) voltage during abnormal condition (c) constantly the electrical quantities which differ during normal and abnormal conditions (d) none of the above

Last Answer : (c) constantly the electrical quantities which differ during normal and abnormal conditions

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

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Which of the following statements represents the main difference between a relay and a contactor? A. Contactors control current and relays control voltage. B. A relay is series connected and a contactor is parallel connected. C. Contactors can handle heavier loads than relays. D. Contactors are made from silver and relays are made from copper.

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Description : The harmonic currents in a power transformer does not cause increase in: a) Secondary voltage b) Core loss c) Copper loss d) Magnetic interference with protective relays

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What are the functions of protective relays

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function of equipment’s used in sub-stations : (i) Earth Switch (ii) Relay (iii) Lighting Arrester (iv) Auxiliary transformer

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Define following terms related to logic families : (i) Noise Margin (ii) FAN-OUT (iii) Propagation delay (iv) Power dissipation

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Define the following terms related to tariff: (i) Connected load (ii) Unit consumed (iii) Fixed charges (iv) Electricity Tax

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Define the following terms: i) Magnetic flux density, ii) Reluctance, iii) Magneto-motive force, iv) Permeance.

Description : Define the following terms: i) Magnetic flux density, ii) Reluctance, iii) Magneto-motive force, iv) Permeance.

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Define the terms : i) Node ii) Branch iii) Loop iv) Mesh

Description : Define the terms : i) Node ii) Branch iii) Loop iv) Mesh

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Description : Define the terms: i) Hardness ii) Toughness iii) Brazing iv) Machinability

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Description :  For the protection of parallel feeders fed from one end, the relays used are: A) non-directional relays at the source-end and directional relays at the load-end B) non-directional relays at both the ... at the source-end and non-directional at the load-end D) directional relays at both the ends

Last Answer : For the protection of parallel feeders fed from one end, the relays used are: non-directional relays at the source-end and directional relays at the load-end

Electrical contact materials used in switches, brushes and relays must possess

Description : Electrical contact materials used in switches, brushes and relays must possess   (A) high thermal conductivity and high melting point  (B) Low thermal conductivity and low melting point   (C) High thermal conductivity and low melting point  (D) Low thermal conductivity and high melting point.

Last Answer : Electrical contact materials used in switches, brushes and relays must possess high thermal conductivity and high melting point 

Reactance relays are employed for Phase faults in :

Description : Reactance relays are employed for Phase faults in : (A) Short lines (B) Medium lines (C) Long lines (D) Any line

Last Answer : Reactance relays are employed for Phase faults in : Short lines

IDMT relays are used to protect the transformer against :

Description : IDMT relays are used to protect the transformer against :  (A) Internal short -circuits (B) Open circuits (C) External short circuits (D) Oil leakage

Last Answer : IDMT relays are used to protect the transformer against : External short circuits

The single phasing relays are used for the protection of?

Last Answer : The single phasing relays are used for the protection of three phase motors.

Which relays are used for phase faults on long line?

Last Answer : Impedance relays are used for phase faults on long line.