Interview Questions.

Question 1. Where Does Negative Phase Sequence Relay Is Employed?

Answer :

Negative sequence relay is employed for the protection of mills and cars in opposition to unbalanced loading that can get up due to segment to section faults.

Question 2. What Is The Operation Principle Of Differential Relay?

Answer :

differential relay operates whilst the phasor difference of two or extra comparable electric quantities exceeds a pre-decided amount.

Electronic Circuits Interview Questions
Question three. Why Distance Protection Is Preferred As Primary Protection Compared To Over Current Protection For Transmission Lines?

Answer :

Distance relay is superior to over current protection for the safety of transmission strains. Some the motives are faster protection, easier coordination, easier application, permanent settings with out want for readjustment, much less effect of the quantity of generation and fault tiers, fault present day value, allows the high line loading.

Question 4. Why Biased Differential Protection Is Preferred Over Simple Differential Protection?

Answer :

Biased differential relay is desired due to the fact its operation isn't laid low with the problem arising out of the distinction within the CTs ratios for excessive values of outside brief circuit currents.

Question 5. Where Impedance Relay, Reactance Relay And Mho Relays Are Employed?

Answer :

The Impedance relay is appropriate for the section faults relaying for the strains of moderate lengths Reactance kind relays are hired for the floor faults even as Mho type of relays are quality acceptable for the lengthy transmission lines and in particular where synchronizing energy surge may additionally occur.

Electrical Engineering Interview Questions
Question 6. What Is Percentage Differential Relay?

Answer :

It is a differential relay where the running modern required to journey may be expressed as a percentage of load modern-day.

Question 7. What Are The Main Functions Of Differential Relays?

Answer :

Differential Relays need to have the subsequent capabilities:

High pace operation
High sensitivity
Adequate short circuit thermal score
Ability to operate function with low values of voltage
Burden need to not be immoderate
There have to be no voltage and modern creep
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Question 8. What Is Meant By “relay Settings”?

Answer :

Relay settings way actual price of the energizing or feature amount at which the relay is designed to function underneath given conditions.

Question nine. Define Plug Setting Multiplier?

Answer :

Plug Setting Multiplier and is defined as the ratio of fault present day inside the relay coil to the pick up cost.

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Question 10. Where Is Directional Relay Used?

Answer :

Directional relay are used when graded time overload protection is applied to ring mains and interconnected networks.

Question eleven. For What Type Of Fault Does Buchholz Relay Is Employed?

Answer :

Buchholz relay offers protection best against transformer internal fault.

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Question 12. How Definite Time Lag Is Achieved In Attraction Armature Relays?

Answer :

The instant type attraction armature can be made a definite time lag or inverse time lag by way of the usage of a oil dash pot, an air escapement chamber a clock paintings mechanism or by placing a fuse in parallel with it.

Electronic Circuits Interview Questions
Question 13. What Is Protective Relay?

Answer :

It is an electrical tool designed to provoke the isolation of part of the electric set up, or to function an alarm sign, in the event of unusual circumstance or a fault. In simple phrases relay is an electrical tool that gives signal to isolation device (eg: Circuit Breaker) after sensing the fault and facilitates to isolate the fault device from the healthy electrical machine

Question 14. What Are The Different Relays That Employed For Protection Of Apparatus And Transmission Lines?

Answer :

The relays which might be commonly employed for protection of transmission strains consist of :

Over present day relay
Directional relay
Distance relay
Under Voltage relay
Under-frequency relay
Thermal relay
Differential relay
Phase series relays
pilot relays
Question 15. How The Electrical Power System Protection Is Divided?

Answer :

The average machine protection is split into:

Generator protection
Transformer protection
Busbar safety
Transmission line protection and
Feeder protection
Electrician Interview Questions
Question 16. How Relays Are Connected In The Power System?

Answer :

The relays are connected to the electricity gadget thru the modern-day transformer (CT) or capability transformer (PT).

Question 17. What Are Different Types Of Principles Of Operation Of Electromechanical Relays?

Answer :

Electromechanical relays function through  concepts.

Electro-magnetic enchantment and electro-magnetic induction. In electromagnetic enchantment relay plunger is attracted to the solenoid or an armature is interested in the poles of the electromagnet. In case of electro-magnetic induction, precept of operation is much like induction motor. Torque is advanced through electromagnetic induction principle.

Electronic Devices and Circuits Interview Questions
Question 18. Action Carried Out By The Relay And Circuit Breaker During Fault Condition?

Answer :

After the relay sensing the fault situation, relay operates and near the ride coils. The effect of this can be circuit breaker function to open the contacts.

Electrical Engineering Interview Questions