Answer / db

1.Whats the use of GNAC(Generator Neutral Accessory
Compartment)
Mounting of neutral side CTs and connection to NGR/NGT
2. why generator or any other system require Neutral
Grounding and not Phase grounding
If you ground a phase, you get a soild line to ground fault
3. what happens if any one of the phase is grounded.
An earth fault
4. if 15kv is grounded directly what will happen, why it
should not be grounded like that
Fault current will flow limited only by the impedance in
the circuit
5. use of of NGTR(Neutral Grounding Transformer and
Resistor) for grounding is helpfull and how
They both limit the earth fault current

Answer / mohit kochhar

1. for connecting equipments like ct, pt's.
2. neutral grounding is for flowing of third harmonic
component present in system to ground and it is grounding
at only one side either supply side or recieving side of
one level voltage like 220kv line or 33kv.. mostly on
sending side.
3 earth fault occur.
4 short cicuit current flow. depends on the impedance of
the generator.
5 NGTR is used for lowering fault current which flows
through neutral to the safe value to dissipated to ground
safely.

Answer / jax

1. To keep Neutral side CT (Differential CT, NCT, Measuring
CT, Cross current CT, Isolator switch, etc.

2. Phase can be grounded by isolating neutral. But the main
aim of grounding can not be achived. The potential
difference between ground and other two phase (ungrounded
phase) will raise to line voltage.

3. It depends on the type of grounding. For ungrounded
system no faulr current will flow. But the potential
difference between ground and other two phase (ungrounded
phase) will raise to line voltage. For Solidly grounded
system phase to ground fault current will be high. For Low
resitance grounding, phase to ground fault current will be
quiet less. For High resistance grounding, phase to ground
fault current will be very low. (I can explain more about
this).

4. Simple. Phase to fault current will be more.

5. Using NGTR single phase to fault current can be reduced.
Because of this stress on the conductor due to fault
current can be minimized. But the stress on insulator is
increased because of rise in phase to ground potential
during fault.

For any doubt in Electrical you can contact me at
jaxp333@yahoo.co.in

Answer / shrikant

In case of any one phase failure the neural will not be
generated and hence the equipment supplying power to all
critical equipments will stop in order to avoid this the
neutral is grounded.

Answer / guest

For correct answer please type question and mail it to
raveesh.pintu@gmail.com


with your answer

Main CT ration is 400/5, meter CT ratio is open type: -/5A. What is the Multiplying factor of the meter, considering same PT ratio.

1 Answers  

Why electricity is generated and transmitted at the values of multiples of 11?

3 Answers  

ALONG WITH MEGGER TEST FOR CHECKING OF MOTOR ,WHY WE MEASURE FOR RESISTANCE AND INDUCTANCE?

4 Answers   L&T,

howmany electrician should maintain for a 1000 kva used plant... in kerala..

0 Answers   Godrej,

how to determine the size of power cable according to load current

1 Answers   JSW,

what type of loads are inductive load & resistive load ?how they different between each other ?

5 Answers  

TRAFO 1. WHY BREATHER IS USED. 2. WHY OIL GOES DOWN IN CONSERVATOR TANK. 3. WHY WE ARE TAKING OIL SAMPLE TAKING FROM BOTTOM OF TRANSFORMER. 4. HOW TO CHECK IR VALUE OF TRANSFORMER. 5. WHY OLTC HAVING BUCHHOLZ TRIP ONLY; WHY NO ALARM. 6. OFF LOAD TAP CHANGER OPERATION PROCEDURE. 7. TR. SHUTDOWN / ISOLATION PROCEDURE. 8. WHEN THREE TRS. IN PARALLEL, ONE TR. IS NOT SHARING THE LOAD – WHAT IS REASON AND WHAT YOU WILL DO. 9. WHY TR. HAS OLTC IN HV SIDE. 10. WHAT IS % IMPEDANCE. 11. WHY TR. RATING IN MVA. 12. WHAT IS VECTOR GROUP IN TR. 13. CONDITION FOR PARALLEL OPERATION OF TRS. 14. WHAT IS TERTIARY WINDING. WHERE IT WILL BE. 15. IF TR. TRIP ON BUCHHOLZ OR TAP CHANGER RELAY, WHAT YOU WILL DO. 16. DIFFERENCE BETWEEN OIL TEMP. AND WINDING TEMP. PROTECTION 17. HOW WINDING TEMP. IS MEASURED IN CAST RESIN TR. 18. DIFFERENT TYPES OF FAULTS IN TR. Trafo - Page-1 of 2 19. WHAT HAPPENS WHEN TR. CHARGED FROM LV. 20. WHAT WILL YOU DO IF MEGGER READING SHOWS ZERO BETWEEN LV WINDING AND EARTH. 21. CAN WE INTERCHANGE BUCHHOLZ RELAY OF MAIN TANK AND OLTC TANK. 22. IF THE LINE BETWEEN BREATHER AND CONSERVATOR TANK 23. LOCKED, WHAT WILL HAPPEN DURING LOAD CYCLE. 24. WHAT IS THE FUNCTION OF OIL SEAL IN BREATHER. 25. WHAT ARE LOCATIONS FOR BUCHHOLZ RELAY FIXED IN POWER TR. 26. WHAT ARE CHECKS IN POWER TR. DURING MAINTENANCE. 27. WHAT IS IMPORTANT WHEN WE CHECK OLTC OPERATION DURING MAINTENANCE. Trafo - Page 2 of 2

0 Answers   KSEB,

can any one help me? 1.what is corona extinction voltage&corona inception volatage 2.what is mean by CFVV?

1 Answers   KSEB,

How does ELCB work when exist earth foult? and How does RCCB work when exist earth foult?

1 Answers  

Why is a plain induction motor unsuitable for wide speed control?

0 Answers  

How much load can be taken for chiller from 1500 kva transformer

0 Answers  

how we can use resistance heating for any domestic purpose???

2 Answers