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 Posted / brad stroh
where did this happen at? what is your location? we
specialize in failure analysis.
Brad Stroh
alineeds.com
Is This Answer Correct ? | 1 Yes | 5 No |
Post New Answer View All Answers
what is the carona effects meaning in HT line transmmission system
what is cathodic protection and why it use in industries?
Please define ohm’s law for a.c (alternating current)?
how to interlock 3 nos MCCBs using under voltage coil. please provide me circuit diagram?
how to calculate slip ring induction motor stator and rotor currents??
Why are lt windings placed near the core?
What is CCM in Electrical ? where can we use this material?
Describe Non I.S. Earth System and why is it used?
harmonics filter
how to avoid electrical shock how capacitor store charges wat are the speed control of induction motors state faradays law flemings left hand rule what is rotary converter wat is transmission and distribution what are the sources of energy abrevation of acb,vcb,sf6,igbt what is output equation of transformer which test copper iron and iron loss are calculated what is eddy current draw a single line diagram (10 marks) draw direct online starter(10 marks)
How do you select the pickup value of the relay?
What is the technical difference between On delay timer and a Star delta timer?
The gauge indicates the number of amps, but what about voltage? How voltage rating (for wire or fuse) determined?
How can we calculate the motor frame sizes?
what is level 2 automation?