Answer / santosh kumar jha

BDV means break down voltage.

This is the test of di-electric strength of transformer oil.
The sample is taken in electrolysis pot and applied a
voltage diff between anode and cathode of the pot , the
diff between the two plate is 2.5 mm.At first we appling
the voltage diff gradually , the voltage near which the oil
looses its insulation property, that voltage is called BDV.

Answer / ilononurb

we can take the break down voltage of transformer oil by
using oil tester. Take oil sample of tr oil and put in to
the testing oil pot with the spere electrode of 2.5mm gap.
Applied gradually the voltage till the oil losses its
dielectric stenght. breakdown voltage will display to the
oiltester meter. As per IEC 156 Standards it should be
40kv.eff.

Answer / rahul sharma

BDV tests is used to test the dielectric strength of the
transformer.
A new transformer oil shol\uld have at least dielectric
strength of 39 KV as per british standards.
Transformer oil used are normally tested using ASTM D877-82
with the KV strength testing,using 1" electrode spaces 0.1"
apart & test voltage increased at 3000 volts\min until it
breaks down. The avg KV obtained after 8 trails is
considered the oil dielectric strength.
Using this test dielectric strength at 30KV & above is
considered good. Dielectric strength between 23 to 29 KV is
considered usable ,but requires filtering, below 23 KV
transformer oil should be replaced.

Answer / ramachandra reddy

On TRANSFORMER OIL BREAK DOWN VOLTAGE test is carried out which is done on field while filling the oil in transformer. This process is also called oil filtration.
1.Take sample from top of Transformer before filtration.
2.The BDV of oil should withstood min 50 KV
3.The gap between the test electrodes sample to be 2.5mm maintained
4.At least 5 sample(top/bottom) should be checked separately while filtration.
5. The samples should withstand 50 kv for 1 min.
5. Take the average of all the samples timings.You will get value.
7.Procedure
a.Voltage should be gradually increased from 0.
b. At one point Flash will take place and that point is
termed as Bread down Voltage

Answer / s.anand

take sample before maintank bottom this coreact methode

why we are used thermistor in motor

1 Answers  

ohms law aplicable

16 Answers   APGenco,

Generally in d.c. circuits the direction of current is from possitive to negative.In a.c.circuits what is the direction fo current flow

4 Answers  

What is C.T, why it is used and what care should be taken for that while connecting?

20 Answers   Bhushan Power Steel,

what is the diff between VCB & ABCB breaker in substaions? explain the operating priciples of VCB & ABCB

1 Answers  

what is thyristor, how is it works

1 Answers   Sony,

What is communication? What are the different stagesin the communication process?

1 Answers  

what is the relative size of single and three phase?

0 Answers   Student,

i have a wire.and the current flowing in that.when we cut the wire then why dont we seen the elactrons....

8 Answers   GM General Motors,

L.A. (Lightening Arrester) is located at a place from where transmission line enters the transmitting substation. So L.A. (Lightening Arrester) is the first equipments which has to encounter with lightening, high voltage surges and switching surges. It has to absorb energy of lightening, high voltage surges, and switching surges. L.A. (Lightening Arrester) is made up of layers of semiconductors. If these layers can not tolerate energy released by lightening, high voltage surges, and switching surges the L.A. (Lightening Arrester) blasts.

0 Answers  

What are the types of piano switches?

0 Answers  

what are the advantages by using IGBT in VSC HVDC than thyristor in conventional HVDC

1 Answers   Bhel, Eskom,