Generator Curves

[wbd]

I have been asked to make some generator curves, a Decrement Curve and a Thermal Damage Curve using EasyPower software. The generator data sheets were provided and I have attached them here.
I have found most of the information but am stuck on where to find:
> Field Forcing current as a per unit value of field current at no load.
> I2t Value
> lower and upper limits in seconds to plot thermal damage curve range.

Thank you in advance

 

[dpc]

Most of this would have to come from the manufacturer of the generator. It can generally be found on the generator data sheet if you can track that down. There can be a wide range of I2t K value depending on the size and type of unit. I've seen values anywhere from 40 down to 10. 30 used to be a fairly standard value for small to medium generators. This K value should be programmed in the generator protection relay for the backup negative sequence current protective function.

The field forcing limit is a function of the exciter type and voltage regulator.

 

[jackaustin]

@wbd The following paragraph was copied from Theodore Wildi's textbook:

When a single synchronous generator feeds a variable load, we are interested in knowing how the terminal voltage E changes as a function of the load current I. The relationship between E and I is called the regulation curve. Regulation curves are plotted with the field excitation fixed and for a given load power factor.

Figure 16.23 shows the regulation curves for the 36 MVA, 21 KV, 3-phase generator. They are given for loads having unity power factor, 0.9 power factor lagging, and 0.9 power factor leading, respectively. In each of the three cases, the value of Eo was set so that the starting point for all the curves was the rated line-to-neutral terminal voltage (12 kV) at rated line current (1000 A).
Do you think the curves (e.g. trend) in Figure 16.23 are correct or not?
By the way, what does the quoted sentence in bold above mean?

Thanks.