Answer / 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.

Sir,In our company there are 3 caterpillar make(capacity:(1) 3.3KV,2.5MW(2)3.3KV,2.5MW & (3)3.3KV,1.9MW) & 1 deutz make (capacity:11KV,3.8MW)gas engines utilised,all are running in paralell. There are three transformer utilised,(1) 6.25MVA,3.3KV/22KV,Impedence voltage:6.7% used for two generator,both are 2.5MW(2)5.5MVA,3.3KV/22KV,Impedence voltage:7.2% used for one generator of 2.5MW & (3) 5.5MVA,11KV/22KV,Impedence voltage:7.8% used for one generator of 2.5MW.all generator breakers capacity of 1250Amps. Sir,I want the details of fault level calculation of generator,transformer individually & for whole system. If you require any information from me.feel free for contact me sir.pl.send the answer of my question as the earliest as possible.

0 Answers   Piramal Healthcare,

---

What is the maximun current carring capacity in per phase for three pole 100anps rating ncb

3 Answers   L&T,

---

What is the formula for selecting the cabels according to load? How to calculate what sq.mm cabel to be used?

0 Answers  

---

How to convert KW to KVA or KVAR OR kvar/kva to kw?

8 Answers  

---

It is being often experienced that due to single phasing fault of any source transmission line of any closed loop synchronized circuit all the power transformers with primary stared trips but the power transformer with primary delta wont, why ?

1 Answers   MSEB,

---

---

practicalLY what is impedence ...?

2 Answers  

---

How to Convert Gen KW to H.T amps ?

2 Answers  

---

what is the diff. between power transformer & distribution transformer.....

5 Answers  

---

What is difference between miniture circuit breaker and module case circuit breaker up to 63Amp.

7 Answers   MSPL,

---

A charge of 240 C is transferred in 2 minutes. The current flowing is:(a) 480A(b) 120A(c) 2A(d) 8A

2 Answers  

---

What is the function of retrip in busbar?

0 Answers   Getco,

---

The ratio of white balls and black balls is 1:2. If 9 gray balls is added it becomes 2:4:3. Then what is number of black balls ?

3 Answers   CTS,

---