Answer / satya prakash

At first do correct your spelling mistakes which indicates
that how much you are either inclined towards reading books
or chatting etc!
----------------------------
I am giving a detailed explanations of this. 1 Sq mm means
area of the conductor only. But it has its own insulation
thickness around it. If it is a sheathed/unsheathed cable
then accordingly it has nominal thickness of sheath added
and the overal max permissible dia of cable can be found
out. It has its detailed calculations. I am giving ex for 1
Sqmm Single Core Cable.
Unsheathed Cable: Nominal Conductor Area:-1 Sqmm, Nominal
Thickness of insulation:-THn=0.6mm, Max Overal Dia:- 2.7mm.
Max Current Carrying Cap:- 11A.
Soln:- Conductor Dia: PI*D*D/4 = 1
=>D= 1.128mm;
Overal Cable Dia= D+ 2*THn = (1.128+2*0.6)= 2.328. Now
10-15% of flexibility due to air inside the cable is added
with it which is equal to: 2.328+ 15% of 2.328= 2.6778 ~ 2.7mm.
Sheathed Cable: Nominal Conductor Area:-1 Sqmm, Nominal
Thickness of insulation:-THn=0.6mm, Nominal Thickness of
Sheath THSn=0.9,Max Overal Dia:- 4.8mm. Max Current Carrying
Cap:- 11A.(Same as unsheathed)
Soln:- Conductor Dia: PI*D*D/4 = 1
=>D= 1.128mm;
Overal Cable Dia= D+ 2*THn+ 2*THSn= (1.128+2*0.6+2*0.9)=
4.128. Now 10-15% of flexibility due to air inside the cable
is added with it which is equal to: 4.128+ 15% of 4.128=
4.7422 ~ 4.8mm.

Answer / k.prakashchandra

Please use Mozilla Firefox for asking questions to avoid
spelling mistakes

Answer / raju

Approx. 1 Amps only

Answer / dijesh

near about 7 amp.

Answer / dhanamjaya

5amps

why we not using 230kv directly why we are stepping down and then stepping up

2 Answers   Siemens,

what are 3 factors when selecting a contactor for a job?

1 Answers  

what happens when power factor leads or lags to electical or home appliances

2 Answers  

In three phase, phase to phase voltage is 440 Volts, but the three phase motors are designed for 415 Volt, 50 hz, why

1 Answers   Shree Ram, Shriram, Sri Ram,

DIFFERENC BETWEEN VOLTAGE AND CURRENT

1 Answers   Wipro,

What is meant by positive and negative feedback?

0 Answers  

why we use DO Fuse in H.T. Line ? What is the purpose of DO Fuse

4 Answers  

Atwhat condition reverse power relay will act?

0 Answers   Equate,

1.differance between onload ups and off line ups.

1 Answers   CTS,

sir, is there any ratio,this much of A.C volt is equal to D.C voltage

3 Answers  

what is difference Auto-transformer and ICT ?

1 Answers   CG, Descon,

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.

9 Answers