Symmetrical Component Transformation: Symmetrical Component Transformation is given by a  set of three balanced voltages (phasors) Va,Vb,Vc is characterized by equal magnitudes and interphase differences of 120°. The set is said to have a phase sequence abc (positive sequence) if Vb … (Read More)

Phase Shift in Star Delta Transformer: Positive and negative sequence voltages and currents undergo a Phase Shift in Star Delta Transformer which depends upon the labelling of terminals. Before considering this phase shift, we need to discuss the standard polarity marking … (Read More)

Sequence Impedances of Transmission Lines: SFigure 10.9 shows the circuit of a fully transposed line carrying unbalanced currents. The return path for In is sufficiently away for the mutual effect to be ignored. Let Xs = self … (Read More)

Sequence Impedances and Networks of Synchronous Machine: Figure 10.11 depicts an unloaded synchronous machine (generator or motor) grounded through a reactor (impedance Zn). Ea, Eb and Ec are the induced emfs of the three … (Read More)

Zero Sequence Impedance of Transmission Line: A fully transposed three-phase line is completely symmetrical and therefore the per phase impedance offered by it is independent of the phase sequence of a balanced set of … (Read More)

Sequence Impedance and Networks of Transformers: It is well known that almost all present day installations have three-phase transformers since they entail lower initial cost, have smaller space require­ments and higher efficiency. The positive sequence series impedance of a transformer equals … (Read More)

Construction of Sequence Network in Power System: Before sections the Sequence Network of various Power System elements synchronous machines, transformers and lines have been given. Using these, the Construction of Sequence Network in Power System can be explained. To start with, … (Read More)