maximum power output of sync generator

[rick.conner]

working on a problem which asks for the maximum output of a sync gen.

given 3-phase, rated for 15kv, 10mva, 0.78pf lag, sync reactance of 14 ohms per-phase and internal voltage of 14.92 at an angle of 14 degrees.

answer says max output occurs when torque angle (angle between internal voltage and phase voltage) is 90 degrees.

Pmax = 3 * 15kv/sqrt(3) * 14.92angle14 degrees / 14 = 27.7MW

can anyone expand on this???

 

[DK PE]

working on a problem which asks for the maximum output of a sync gen.

given 3-phase, rated for 15kv, 10mva, 0.78pf lag, sync reactance of 14 ohms per-phase and internal voltage of 14.92 at an angle of 14 degrees.

answer says max output occurs when torque angle (angle between internal voltage and phase voltage) is 90 degrees.

Pmax = 3 * 15kv/sqrt(3) * 14.92angle14 degrees / 14 = 27.7MW

can anyone expand on this???

I think it is a version of P =((Eg *Vt)/X )sin δ, where P is Power per phase, if the voltages are per phase, δ is the torque angle, and X is reactance per phase

So the first 3 in your solution takes care of adding for all three phases

- the 15kV/√3 is the bus or terminal voltage line to neutral

- the dividing by 14 is the X in ohms/phase

- assume max power so sin δ = 1

- it seems like they assumed the given 14.92kV is a phase voltage

Either the Stevenson or Wildi texts cover this.

 

[ElecPwrPEOct11]

^ +1.

I've seen this problem before, can you remind me where? It'd driving me crazy.

 

[rick.conner]

complex version 1 problem #20

also DK thanks for the good explanation.