Answer / s bagchi

Step1: convert the kva or kw load into amps by dividing
with the respective voltage & pf in case of kw.
Step2: refer a cable catalogue & derate the current
considering temperature rating factor & group rating factor.
Step3: select a cable size considering the derated current.

at first you need to calculate the min cable size in case
of ht cables considering short time current & the fault
clearing time of the upstream breaker.

Answer / harshad

First calculate the current.
Eqn for 3phase: Current= Connected load in watt/sqr root of 3*415*pf

Eqn for 1phase: Current=Connected load in watt/230
Select the cable size from the chart with respect to the current.
pf(power factor) is 0.8 or 0.9

What is the safety protection? Name the protections of Transformer?

1 Answers   HSL,

---

How do you select a cable size(Cu & Al) for a particular load?

2 Answers  

---

why wire sizes are 3/29 or 7/29 and why not wire sizes are 2/29 or 6/29?

0 Answers   OGDCL,

---

We have 2 Nos. Transformer with the capacity of 2000KVA and 1250 KVA and currently using only one 2000KVA T/R during operational hours while non- operational hous 1250 KVA T/R also used to reduce T & D losses. Similarly, 2 capacitor bank of 500KVAR and 300 KVAR also installed to balance reactive power. Now problem is around 1000 KW load PF is not maintaning 0.99 as 350 KVAR capacitor is in healty condtion. Now the PF is maintain 0.95 to 0.96.

2 Answers  

---

how to calculate of which rating transformer should be selected? take any example

2 Answers  

---

---

How would you calculate power loss in a resistor?

0 Answers  

---

what is the current setting for different relay protection for transformer .

0 Answers   Crompton Greaves,

---

While HT line put on to activate ACB in low tention panel VCB tripping instantly.why it happens

0 Answers   Engineering,

---

How many types of earths are there?What is the maximum ohms of earthfit?

3 Answers  

---

How can we select a capacitor Bank.? i need a standard formula for that.?

3 Answers   ABB, Ace Info, HAL, IKK, MahaGenco,

---

What is the causes Power Factor become leading and what is the effect of Electrical system ?

2 Answers  

---

Which type starter is used for synchronous motor?

2 Answers   Equate,

---