Question

•The 3-phase system consists of a generator, circuit breaker, power transformer and extra high voltage transmission line.

•The generator is rated at 60Hz, 1559Mva and 24kV. The sub-transient reactance is 2*%. The winding connection is wye with the neutral grounded.

•The transformer is a 1550Mva, 3-phase, shell type, 2-winding transformer with a 24kV delta winding and a 525kV grounded wye winding. Neglect saturation and core losses. The exciting current is 1.0% of the rated current. The capacitance of each low voltage winding to ground is 5000pF. The through impedance is 5% with an X/R ratio of 5+.

•The transmission line is rated at 525kV and is 10+ miles in length. Following are the positive and zero sequence characteristics of the line:

• Zero sequence R = 0.578 ohms per mile

• X = 1.68 ohms per mile

• Y = 5.0 micromhos per mile

• Pos. sequence R = 0.0254 ohms per mile

• X = 0.595 ohms per mile

• Y = 7.034 micromhos per mile

Draw a one line diagram of the system with any needed calculations for PSCAD input

Answer 1