Interested to Buy Any Domain ? << Click Here >> for more details...
How do we measure earth fault current in Generator
Transformer(20/420kv),Station Transformer(20/11 kv) and Unit
Transformers(20/11kv) for our plant system, since these
don't have any Neutral earth Fault relay connected to their
Neutral Earth?
But for Unit Service transformers(11/.433 Kv) we have an
Earth Fault Relay connected to its neutral earth.Why is such so?
- 1 Answers
- 4710 Views
- NTPC, I also Faced
- E-Mail Answers
Answer Posted / a.p.nanjappa
I assume your generator rating is around 250-315MW.
GENERATOR TRANSFORMER IS YN-d1 or d11, 420kv power
transformer is provided with neutral bushing and solidly
grounded to earth system (U,V,W-N). YOU CAN MEASURE THE
EARTH CURRENT WITH CLAMP ON METER.
GENERATOR 20KV OUTPUT IS CONNECTED WITH lv side of
generator transformer by bus duct. there is a voltage
transformer, 2 winding y/y or three winding VT Y/y-
opendelts. This open delts voltage indicate the fault in
20kv system.
Genrator is provided with 90% and 100 % earth fault
ptortection.
Generator neutral is connected with generator neutral
grounding transformer. Generator neutral transformer
primary is connected to genrator neutral point and other N
is connected to earth. at this point ,You can measure earth
current by clamp on meter.
I assume you have a Generator circuit breaker.
Generator bus is 20kv. This sw.gr feed stn tranformer -
20/11kv system.This station 11kv feed the auxilary
transformers. Vector group of this stn transformer is D/d.
Also unit transformer is 20/11kv. this 11kv bus feed motor
and auxiliayr transformers. vector group is also D/d.
your medium voltage operates as isolated ground system
Unit service transformer is 11/.433 , thereforn vector
group is D/yn. your low voltage feeder need a nuetral.
therefore neutral is brought out. three phase 4 wire, and
230v-n .
please send the rating of transformer. we can explain you
more.
| Is This Answer Correct ? | 0 Yes | 1 No |
Post New Answer View All Answers
what questions are asked in the interview for the post of an electrical maintenance engineer in FMCG companies?
hi, in the event earth grounding is not available in a project, is there any other way to make the elcb work? fyi, i have an instant water heater (6.5kw) installed, however if there is grounding in the heating element inside the heater assembly, i will get grounded. thank you in advance to those who will answer my question.
What are the advantages of vscf wind electrical system?
Why we do 2 types of earthing on transformer (ie:)body earthing & neutral earthing , what is function. I am going to install a oo kva transformer & 380 kva dg set what should the earthing value?
What is core CT & it's function?
What do you mean by phasors?
What is the approximate value of stacking factor?
A ray hit a smooth regular surface at an angle of 20 from the normal. Calculate : 1. The angle btw the incident and reflection ray. 2. The angle of deviation.
what is counter poise conductors
what are different types of electrical windings? i know the distributed winding ,concentrated winding etc but i want some detailed information, in what condition we will use distributed,concentrated windings what are the difference between them which is best, how induced emf changes by using different types of windings 20 hours ago - 1 week left to answer
How much pf maintan in dg set in 6o% load,when Dg runnig Neutaal Earthing removed what happen.
why constant voltage transformer should be start without load? and if started then what will happen?
What is control system?
What are the material used for resistor?
i ha done my 10th with 71% ,ITI with 81% 11th with 75% 12th 43% apprentiship with 71% in SAT i secure 1390 ,TOEFL 27 i was refused four times and in all me interview visa officar told that i am not Qualify for study in USA but i completed my 12th yes i got low persentage in my 12th but i seen to much student they already got visa with them 3 or 4 backlocs so why they are refused me ?
