Turbine Generator and Step-up Tansformer Size

A

Thread Starter

adel

in our country asking the private generation plant to provide the power to the Grid and the guarantee generated power is considered after the Step-Up transformer not at the generator terminal means I.e. 500Mw @0.9 pf after Step-up transformer. my question is how the power factor value affecting the size of Generator and Step-up transformer if the guaranteed values is at generator terminal instead of after step-up transformer?
 
Adel... I’ve interpreted your query as two-fold: 1) Why is the Point-of-Delivery (PoD) on the Utility side of the GSU Xfmr, and not on the Supplier side; and 2) How does a change of Power-Factor impact the situation?

The answer to the first question has to do with ownership of GSU power losses! If the PoD is on the Supplier side, the Utility would have to pay for GSU losses! Conversely, if the PoD is on the Utility side, the Supplier absorbs losses!

Adel... at this point I'm not sure I properly addressed your post. But if it is, do you want additional information detailing how Power Factor impacts the situation?

Regards,
Phil Corso
 
thank you phil.

my question, how the size of generator and GSUT will change if the guaranteed power changed from 500 MW @0.8 pf to 500 MW @ 0.95?
 
dear Phil,

thank you and I am sorry I phrased my question wrong. my question how the size of Generator and GSUT will change if the PoD changed from the GSUT to the generator terminal? (let us assume the guarantee power is fixed 500 MW @ 0.8 Pf)
 
Adel... A transformer's required rating is always given in MVA, never in MW. Also, Power Factor is never listed in the xfmr's Nameplate as a design rating!

As an example, consider the two operating conditions you cited:

a) For a contracted capacity of 500MW @ 0.80 PF, the xfmr's capacity is 500/0.80 or 625MVA!

b) For a contracted capacity of 500MW @ 0.95 PF, the xfmr's capacity is 500/0.95 or 525MVA!

Thus, during project dsign the worst-case PF condition is selected. In your case it is 0.80, yielding a 625MVA xfmr!

Phil
 
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