Interview Questions.

Q1. What Is The Power Station?

Power Station is an area wherein Power is Generated and Trmitted , eg. Thermal power station, Hydel strength station, Nuclear strength station and many others.

Q2. What Is The Bundle Conductor And Why Is Used ?

A package deal conductor includes two extra parallel subconductors at a spacing of several diameters.This is use to reduce the corona and pores and skin impact.

Q3. What Is Critical Disruptive Voltage?

The minimal voltage at which the breakdown of the insulating properties of air happens and corona begin is called D C V .

Q4. What Are Internal And External Faults?

Faults that occur within the zone are termed as Internal Faults and that arise outside the sector of protection are termed as external faults (also can be called as thru faults).

Q5. How To Set The Operating Time Of The Relay?

Naturally when a fault occurs it's far sensed by way of each the number one and backup safety. As the working time of number one relay is less than that of the backup relay, it'll perform first. There might be an overshoot time (because of second of inertia of moving relay device).

Consider a primary relay A having running time of zero.1 sec. Assume circuit breaker working time as 0.Five sec and overshoot time as zero.Four sec. Now the working time of backup relay B will be 0.1+zero.5+0.Four= 1 sec.

Q6. Explain The Operating Principle Of Dtoc And Idmt Relays?

A Definite time over modern-day relay (DTOC) may be adjusted to experience out at a exact amount of time, after it selections up. It has a time adjustment setting and pickup putting.

The operating precept of IDMT relay is based totally at the concept that more severe a fault is, the faster it must be cleared to keep away from harm to equipment.

Q7. When Will You Go For Idmt And Dtoc Relays?

Though IDMT relays offer massive development in fault clearing times over DTOC relays, DTOC relays have their personal advantage.

Consider a system where .

Since the fault modern-day as a characteristic of fault region is proportional to , it'd continue to be extra or much less regular in the course of the duration of feeder. Therefore, the IDMT relay will not be of a great deal help. So DTOC relays may be used for traces which can be quick in duration.

Q8. When Are The Directional Relays Used?

Directional relays are used in particular in unmarried cease fed system of parallel feeders, ring most important feeder device and so forth.

Q9. What Is Slack Bus ?

Slack Bus is the answerable for the delivering losses inside the strength system. On this bus the significance of voltage and segment attitude are targeted. This bus is first to reply to a converting load circumstance.

Q10. How Do You Select The Pickup Value Of A Relay?

The relay need to permit normal load as well as a sure diploma of overload to be supplied. So the pickup price of the relay need to be extra than most load. At the identical time, the relay must be touchy enough to respond to the smallest fault. So, pickup cost need to be much less than the smallest fault current.

Q11. Why Does The Adjacent Zones Of Protection Overlap?

If the adjoining zones do no longer overlap there may be a few portion of the electricity gadget which is left out unprotected.

Q12. What Is Skin Effect ?

When the AC handed thru the conductor the density of the modern-day isn't uniform over the move-phase of the conductor, the density of the cutting-edge could be very excessive close to the floor of the conductor and really low at center this effect is referred to as skin effect. This impact is simplest inside the ac.

Q13. What Do You Mean By Reach And Reach Point Of The Relay?

The farthest factor from the relay which continues to be within the area of protection is referred to as attain factor and the distance among relay and reach point is referred to as reach.

Q14. How Many Types Of Fault Occurs In The 3p Power System ?

Faults in the three P system can be categorised under the subsequent :-

single line to ground (LG) fault

line to line (LL) fault

Double line to ground (LLG) fault 

Three Phase brief circuit (LLL) fault

Three phase to floor (LLLG) fault

Q15. What Is Difference Between Fuse And Breaker?

Fuses are burned at the time of over modern flows in the circuit however breakers are just open (now not burn) on the time of over cutting-edge waft. Fuses are used in most effective one time however breakers are utilized by a couple of number of times.

Q16. What Is Different Between Resistance Grounding System And Resistance Earthing System?

Resistance grounding device me connecting the impartial point of the weight to the floor to carry the residual present day in case of unbalanced situations through the impartial to the ground whereas resistance earthing gadget is finished in an electric powered system on the way to shield he gadget in incidence of fault within the system.

Q17. What Do You Mean By Zone Of Protection?

The protection is organized to provide a ring of protection around every and each element of power gadget. If there is any fault related inside the ring the relays associated with it ought to experience all the allied circuit breakers on the way to dispose of any defective element from rest of the electricity gadget. This ring of protection is referred to as ‘Zone of safety’.

Q18. How Many Methods Uses For The Load Flow Solution ?

Gauss-seidel approach the usage of Ybus

Newton- Raphson approach (NR)

Power go with the flow through line and slack bus electricity

Decouple load flow technique

Fast Decouple load drift technique.