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Associate

Join Date: Oct 2010
Posts: 53

Sudden Short Circuit Test

10/26/2017 6:21 AM

The sudden short circuit tests are performed to determine transient and sub transient characteristics of a generator. How important is the voltage level.What i want to ask is what difference will it make to perform test at 50% or 80% or 105% of the rated voltage.Higher the voltage higher will be risk

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Guru

Join Date: Oct 2008
Posts: 39909
Good Answers: 1588
#1

Re: Sudden Short Circuit Test

10/26/2017 8:38 AM
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Guru

Join Date: Apr 2010
Posts: 5759
Good Answers: 577
#2

Re: Sudden Short Circuit Test

10/26/2017 8:51 PM

Depends on how far you want the wires to jump...

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Power-User

Join Date: Sep 2016
Location: SPAIN
Posts: 167
Good Answers: 7
#3

Re: Sudden Short Circuit Test

10/27/2017 1:33 AM

If short circuit test is done for different voltage levels, it must be to minimize the impact of the damage.

If something goes wrong, you would want to inspect the device, and it is unlikely you could do that if it gets completely destroyed.

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Power-User

Join Date: Mar 2010
Location: BHOPAL, INDIA
Posts: 183
Good Answers: 16
#4

Re: Sudden Short Circuit Test

10/27/2017 4:05 AM

The sudden Short circuit test is primarily conducted on Prototype machine to prove the adequacy of Generator stator winding overhang support system. This test is repeated on subsequent machine to prove the workman ship of the manufacturing process.

This test is not performed to determine the transient and sub transient reactance. There are other methods for determining these parameters. However, if this test is conducted for any of the reasons stated above, then the stated parameters can also be determined as by product.

The voltage level at which this test is performed depends on many factors which includes size of the generator, facilities available at the manufacturing plant (capacity of the short circuiting switch, cables carrying the short circuit current, fixing arrangement of the generator on test bed foundation). Theoretically, the test should be conducted at 100% (or 105%) voltage. But it is not always possible to follow this due to the fact that fixing of generator at test bed cannot be as strong as that at the power station with permanent foundation block, fixing bolts etc. off course, limitations stated above will be there as well. So test is performed at voltage mutually decided between the manufacturer and the customer. Many time customer gets satisfied by copies of test conducted on prototype generator or other generator (may be not less than 5 years old ).

The difference on parameters obtained by conducting test at voltage other than rated voltage would be that the forces on the overhang support system would be lesser at lower voltage and the parameters (reactances etc) would at that level of saturation at which the test is performed.

There is no risk (other then proper fixing on foundation) in conducting test at rated voltage, if conducted with due preparations, as generator is suppose to withstand this test without affecting its performance. Some time argument is given that this test may consume some life of the generator due to enormous forces acting of winding overhang, but yes checking the design adequacy and workmanship are equally important.

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