Answer / praveen

breaker capaciy taken by 132kv for example 133*1.55 times
capacity 145kv suitable for beaker

Answer / raghavendran.r

Step1: Calculate the system MVA.I have calculated that as 1.732*6600*800 = 9.144MVA. I have taken it as 10 MVA for easy calculations further.From the system MVA find out the Fault MVA value using the per unit impedance.i.e

Fault MVA = System MVA /P.u.Impedance.I am taking iot as .1
Hence we arrive at the Fault MVA.From this condition we get to know the Short circuit current as Isc = Fault MVA/Sys Voltage(6.6kV).

Usually, for a 6.6 kV system, the short circuit withstand rating is 40kA for 1 second.The Momentary current or making current is 2.55 times the Max. short circuit current.hHence we arrive at 100kA(Peak)

describe the phenomena of vacuum interruption in C.B

0 Answers  

---

for distribution line ratio of x/r 1.<0.1 2.>10 3.>1 4.<0.01

3 Answers   HAL, HPPSC,

---

the rating of fuse wire i always expressed in what?

3 Answers  

---

what is the difference between 2 way and 4 pole selector switch???

0 Answers   Allied Group,

---

When we use air circuit breaker, it has O/L protection ,time delay SC protection, Instataneous SC protection & ground fault protection. They all have some setting range. But what is the suitable/allowable setting for the above protection which will be safe for the equipment? For example-O/L protection setting have a range of (0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.8,0.9,1.0)xIn Time delay SC protection have a range of (1.25,1.5,2,3,4,6,8,10,12)xIn Time delay setting is 0.02,0.1,0.2,0.3,0.4 Instataneous setting is fixed to 20xIn Gound fault setting is given 100A,300A,600A,900A,1200A This setting are for 2500A ACB. So what will be the basic allowable setting for the above protection? is there any formulae to calculate this<

0 Answers   Lupin,

---

why transformer rating in KVA or MVA instead of KW n MW??

3 Answers  

---

A Generator is in running condition and Rotor earth fault alarm is coming.How to check on line(i.e in running condition) whether there is actual earth fault in rotor or not.

0 Answers  

---

In a voltage-controlled current source A A current booster is never used B The load is always floated C A stiff current source drives the load D The load current equals Isc

0 Answers  

---

Why only 1 CVT in Y-phase is used for synchronization in 3 phase power system?

1 Answers   Reliance,

---

show me the diagram of three phase wiring and also tell me hoe to take the readings of megger testing

2 Answers  

---

i need list of swg(standard wire guage) or area of conductor v/s current carrying capacity of conductor copper & alluminium...

0 Answers  

---

what is the AC Plant and how can do the work with parts and picture tell us 150 Tr

0 Answers   Wipro,

---