Introduction to development of Modern power system
- As shown in Figure, the Synchronous Machine Model Contain three stator windings which is separately distributed.
- The winding currents are denoted by ia , ib and ic.
- The rotor contains the field winding the current through which is denoted by if .
- The field winding is aligned with the so-called direct ( d ) axis.
- We also define a quadrature ( q ) axis that leads the d -axis by 90°.
- The angle between the d-axis and the a-phase of the stator winding is denoted by θd.
Schematic diagram of a synchronous generator
Let the self-inductance of the stator windings be denoted by Laa, Lbb, Lcc such that
And the mutual inductance between the windings be denoted as
The mutual inductances between the field coil and the stator windings vary as a function of θd and are given by
The self-inductance of the field coil is denoted by Lff.
The flux linkage equations are then given by
For balanced operation we have
Hence the flux linkage equations for the stator windings (1.85) to (1.87) can be modified as