Answer / p.v.subbaiah

Earth resistance can be measured with earth megger.There is
some values for the earth resistance.For 33kv s.s the earth
values should be less than 1 ohm.etc.
To control earth
resistance with in the limited range we have to monitor the
earth pits regularly.If the values are beyond the limit
then pour salt,coal and water.Then check the values.If your
sub-station is at dry area then you have to pour some
chemical called BITUMAN COMPOUND in the earth pits.Then
your earth values are safe.

Answer / meenakshi

i vud lyk to enhance mr.subbiah's answer...

for large power stations- 0.5 ohm
major power station - 1 ohm
small substation - 2 ohm
other cases - 8 ohm
controlling here means the measures 2 b taken to reduce the
earth resis value
- use no of earth electrodes in parrlel connection
- v can replace the existing electrode by a larger dia
electrode
- depth of pit can b icreased in order to get more moisture
n water content in the soil
-n the important method as mentioned by subbiah

Which UPS (inverter) is better and why ? 12 V inverter and 24 V (two 12 V batteries in series) inverter which is better ......... which has the longer backup which has the greater charging time which has the greater discharging time thank you

2 Answers  

---

tan delta test of current transformer.

3 Answers   NTPC,

---

transformer test

4 Answers  

---

10 hp motor ,7.5 kw ,960 rpm, full load current 15.5, delta connection so how much take current no load trial time. any formula please give..... second question :- what is different between brekar control wiring and motor starter control wiring

1 Answers   MSP,

---

we have 3 phase 4 wire supply 230/415 V.AC and our distribution is single phase or we have all single phase 220 v,ac operated appliances. and noted the current with help of clamp meter Red to N = 20 Amps. Yellow to N = 45Amps and Blue to N = 30 Amps ( total is 95 Amps ) what will be neutral current on the main .

1 Answers   ABC,

---

what is the meaning of number in (11, 31, 61,14, etc. CDG11, CDG31, CDG61, DDT32

0 Answers  

---

What is the function of attenuator in cro?

0 Answers  

---

what must be the mf for a meter with the following conditions. line ct ratio-100/1 line pt ratio- 220kv/110v meter pt ratio- 3X63.5V meter CT ratio- -/1 A

1 Answers  

---

How to find out damper winding failure for synchronous machine?

0 Answers  

---

What is the Load Capacity of Panther conductor (0.2) and dog conductor (0.1)

1 Answers   Greenko Group,

---

IF TVM OF TRANSFORMER SHOWS POWER FACTOR ON 33 KV SIDE AS 0.97 LAGGING AND ON 132 KV SIDE IS 0.75 LEADING.IS THIS CORRECT.WHERE IS PROBLEM.

0 Answers  

---

two 100W/230V bulb are connected in series. what would be the voltage drop across 1 bulb

6 Answers  

---