#Single line diagrams generator

Reactance diagram is drawn by neglecting the effective resistance of generator armature, transformer winding resistance, transmission line resistance line charging and the magnetising circuit of transformers. The impedance diagram can further be simplified by making certain assumptions and reduced to simplified reactance. The three separate impedance diagrams are used in the short circuit for the studies of unsymmetrical fault. Three separate diagrams are also used for representing the positive, negative and zero sequence networks. It is also called positive sequence diagram. The diagram shown below is the balanced 3-phase diagram. Neutral earthing impedance does not appear in the diagram as the balanced condition is assumed. The load is assumed to be passive and are represented by a resistive and inductive reactance in the series. In impedance diagram, each component is represented by its equivalent circuit, e.g., the synchronous generator at the generating station by a voltage source in series with the resistance and reactance, the transformer by a nominal ∏-equivalent circuit. So for simplification, the impedance diagram is used for representing the power system components. It is difficult to draw the line diagram of the few components. The figure shown below represents the single line diagram of a typical block system. Generator and transformer connections, star, delta and neutral earthing are indicated by symbols drawn by the side of the representation of these elements.Ĭircuit breakers are represented by rectangular blocks. In the single line diagram, the system component is usually drawn in the form of their symbols. It is not necessary to show all the components of the system on a single line diagram, e.g., circuit breaker need not be shown in the load flow study but are the must for a protection study.

Single line diagrams