Question { 19681 }
On load tap changer (OLTC) explode?
Transformer
Vector group: Ynd11
Rated Power: 353MVA
Rated Current: 693A
Voltage:294/20KV
OLTC
Type: T III Y1000 110/c 12193w
Max Operation Current: 295A
Step Voltage: 550V
Arrangement in Tx windings: Y Connection
Problem: Damage of Unit 1 Generator Transformer On Load Tap
Changer (OLTC)
Description of Incident:
9.00 a.m. :- Generator No Load test on excitation system
started
10.30 a.m :- Carried out AVR change over
test
11.30 a.m :- Preparation for Generator Manual Synchronizing
test
12.00 a.m :- Manual Synshronizing test started.
Observed incoming generator voltage higher than running voltage.
CECR operator operated Generator Transformer OLTC to bring down
the incoming generator voltage
12.03 a.m :-Generator Transformer abnormal alarm operated at
Gen.Control Desk (CECR)
CECR operater at Generator transformer bay informed that the
transformer
oil splashed out from OLTC.
CECR operater informed that he heard explosion inside OLTC.
Observed Oil level & Oil Flow alaram operated at Tranformer
local annunciator.
12.05 am :- CECR operator 'Open Gen Field Breaker”
12.10 a.m. :- Elec1 team inspected the OLTC and found the
OLTC rupture disk was broken
and oil spilled at OLTC area.
- Elec1 found the OLTC top cover bulging.
Do anyone know why and possibility cause happen in this OLTC.
Answer
Is This Answer Correct ? | 1 Yes | 1 No |
Question { 6754 }
I am getting differential earth fault in my transformer
realy , i have checked all its CT & control wiring but do
not get fault, Please help
Answer
Is This Answer Correct ? | 1 Yes | 0 No |
Question { Navrachana University, 93499 }
What is the working of AVR in AC generators?
Answer
Is This Answer Correct ? | 6 Yes | 7 No |
Question { 3926 }
what is load balancing. what maximum load diffence is
allowed between phases.
Answer
Is This Answer Correct ? | 1 Yes | 4 No |
Question { 4982 }
if we want ot select cable size with reference to load
current it take than what is the formula and it is same for
aluminium or copper?
Answer
Is This Answer Correct ? | 2 Yes | 0 No |
Question { 2353 }
whenever any squirrel or a crow falls on the transformer
input line then there is a big explosion and 440 volts of
power is being discharged through the neutral line due to
which appliances in off mode are also burned.we have
earthing for the transformer as well as the bus bar
chamber.why is it happening?
Answer
Is This Answer Correct ? | 0 Yes | 0 No |
Question { 3313 }
In case of power/distribution transformer what is percent
impedence?
Answer
Is This Answer Correct ? | 1 Yes | 1 No |
Question { 2672 }
whenever a squirrel or a crow gets tangled near the out put
of the feild transformer there is a discharge of 440 volts
of current through the neutral due to which my appliances
blow up causing a huge bang.will the RCCB help in these
conditions
Answer
Is This Answer Correct ? | 1 Yes | 1 No |
Question { 2782 }
what could be the possible reasons for copper cable to have
low insualation?
Answer
Is This Answer Correct ? | 3 Yes | 1 No |
Question { 2804 }
wht d.c produces corrosion
Answer
Is This Answer Correct ? | 1 Yes | 0 No |
Question { 2194 }
Please give me a ansver for why currant transforme noe
point should erthing
Answer
Is This Answer Correct ? | 1 Yes | 0 No |