Generator Reactive Capability Plot

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Thread Starter

Blackstud

Can someone please throw some light on reactive capability curves for generators, and if they are applicable to an infinite bus?
 
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Phil Corso, PE

Blackstub... Yes, they are! I suggest you search the Control List Archives. There are quite a few topics, and many responses covering the topic in detail!

Regards, Phil Corso, PE ([email protected])
 
Reactive capability curves, or plots, are used to describe the operating limits of the generators they are provided with--in other words, a reactive capability curve is not a one-size-fits-all document. Since generators "produce" both real current and reactive current--and the production of both results in the generation of heat in the generator (either in the stator or the rotor or both, depending on how much of either--real- or reactive current--is being produced), reactive capability curves describe how much of either can safely be produced for given "gas" temperatures ("gas" being the medium used to cool the generator, either air or hydrogen, in some cases very large generators also have stator cooling, also, using water or some other liquid).

Operating the generator "outside" the limits defined by the reactive capability curve can cause damage to the generator--either the stator insulation or the rotor insulation, or both, depending on the operating condition(s). Excessive heat damages the insulation used on the conductors in the stator and the rotor. When current flows through a conductor--either real- or reactive current--heat is generated, and there are limits to how much heat can be "removed" from a generator.

The reactive capability curve describes the limits of safe operation (meaning the "heating limits" of the generator)--which, if exceeded, will usually void any warranty and damage the generator insulation, leading to a possibly even more catastrophic failure!

As Mr. Corso has said, there have been numerous posts on this subject on control.com, and the search feature of this site is one of the best of any forum of this type--regardless of subject. If you have other, more specific, questions let us know!

markvguy
 
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