Main Causes for Negative Phase Sequence Occurring in Generator

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Thread Starter

Devesh

What is negative phase sequence? what is the main causes for negative phase sequence occurred in Generator? if this fault occurred in generator, what will do by us for trouble shooting the fault?
 
Devish...

I suggest to search Control.Com Archives using "Search the Site" box in the upper right-hand corner of each page. There are some 50+ "Negative Sequence" posts!

Regards,
Phil Corso
 
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>What is negative phase sequence?

go through symmetrical fault chapter in power system engineering. Any fault can be derived into symmetrical fault of positive + negative + zero sequence components. these symmetrical faults can be analized easily through mathematics.

> what is the main causes for negative phase sequence occurred in Generator?

Any unbalance in the magnetic circuit will reflect an unbalance in generated voltage which will cause a negative sequence voltage, this negative seq voltage is purely mathematical. Practically you can only observe the unbalance voltage in oscilloscope. Apart from this any external fault which cause an unbalancing component in the generator voltage is also responsible for negative seq voltage /current.

> if this fault occurred in generator, what will do by us for trouble
> shooting the fault?

when heavy external fault occurs specially unbalanced (single phase/two phase fault) the electrical relay will derive the negative seq component from it and you will notice negative seq fault. when fault occurs practically you can do nothing within its operating time it is so short duration. But you can take thousands of precautions so that fault occurring are minimum.

and the unbalanced excitation part can be dealt with generator manufacturer only.
 
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