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prabhurak
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Transformers

05/21/2012 12:21 PM

what are all the tests is important before precharging the x-mers?
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redfred
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#1

Re: Transformers

05/21/2012 12:54 PM

Passing your electrician qualifying exam is the most important test. There will be many more tests and exams before that but one does not have to pass all of these earlier exams, just the critical ones.

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jack of all trades
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#2

Re: Transformers

05/21/2012 2:40 PM

Well we check the nameplate to ensure we have been supplied the correct one (you may be surprised how important this first check is).

A check of the oil level and a kick of the tires is always good too.

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lyn
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#3

Re: Transformers

05/21/2012 5:40 PM

This site is not the proper place to go for an education.

Maybe try here:

Basic Electricity - Electricity Forum
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nagaronlinepowers
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#4

Re: Transformers

05/22/2012 1:50 AM

When completing the installation of electrical transformers several tests are required to determine the electrical, thermal and mechanical suitability for the system where they will be applied or used. Most of the tests performed on power transformers are defined in national standards created by IEEE, NEMA and ANSI.Electrical Transformers: Test TypesField testing can be divided into three categories.Acceptance testsPeriodic testsFailure Tests.

Automatic Electric Servo Stabilizer
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nascon
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India - Member - PROFESSIONAL Engineering Fields - Power Engineering - electrical planning - designing

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#5

Re: Transformers

05/22/2012 2:20 AM

First of all Mr Prabhu You must be aware @ Primary/secondary of Tr with it's voltage level as well @ Tr use like power, distribution .lighting and so on.

You must as well know if the Tr is dist or Light than @ it's cooling as Oil type or dry type etc.

Well, you must elaborate your question as what tests for pre charging? what do you mean by charging and pre charging?

Give detail @ TR you wants to charge.

Do you know about IS code , which mentions routine tests and type test , The mandatory test pre dispatch needs to refer and that is @ Ur answer
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prabhurak
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#8
In reply to #5

Re: Transformers

05/22/2012 1:02 PM

Dear Mr. nascon,

voltage 6.6KV/415V, distrbution tr, dry type, 2.0MVA
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nascon
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#10
In reply to #8

Re: Transformers

05/23/2012 3:08 AM

before commencing the commissioning, please ascertain as the Transformer under installation is physically OK, The all accessories are properly attached/assembled.

Earthing etc., are in line with requirement.

Since it is 6.6 KV -415 that means this may be one of the transformer in down stream of distribution network.

The cables/jumpers as applicable are connected with proper joint box/lugs etc.

1. take insulation test with megger for primary phase to phase, phase to body

2. as above for secondary, (The secondary load side panel relay coordination, and all other megger results needs to be checked by 415 volts after megger and prior to switching 6.6 kv power.

3. Between primary to secondary earth

4. Apply 415 volt in primary side of 6.6 kv side keeping secondary open

5. After a Hrs disconnect the supply of 415 and charge the 6.6 KV power on satisfactory results of above readings

After a while start secondary feeder switching on one by one.
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PWSlack
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#6

Re: Transformers

05/22/2012 3:25 AM

Did the thought of reading the transformer manufacturer's installation and commissioning instructions not occur?

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electricalexpert65
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#7

Re: Transformers

05/22/2012 9:52 AM

Is it "pre-charging" or "charging"? What is pre-charging?
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jack of all trades
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#9
In reply to #7

Re: Transformers

05/22/2012 2:52 PM

What is pre-charging

Standing behind a wall and ramping the primary voltage up with a variac with the transformer unloaded the very first time. For when you really have 'confidence' in the transformer supplier or repairer.

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nascon
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#11

Re: Transformers

05/23/2012 3:14 AM

it is charging or you can say it is commissioning

The assembled Transformer with accessories, cables,jumpers, earthing, NGR is any etc., should be adequately and properly installed/erected.

On satisfactory insulation test as per input voltage level setting Load tap change suitably , Transformer are ready for commissioning.
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Users who posted comments:

electricalexpert65 (1); jack of all trades (2); lyn (1); nagaronlinepowers (1); nascon (3); prabhurak (1); PWSlack (1); redfred (1)

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