Single Line diagram of an Electrical system

SINGLE LINE DIAGRAM

Single line diagram

In general electrical power systems are represented by a one line diagram (or) single line diagram

A single line diagram of a power system shows the main connections & arrangements of components in a simplified manner

Pictorial representation of the entire power system from generating end to the consumer premises is known as single line diagram

Standard symbols

Single Line diagram of an Electrical system

Ø  One line diagram of a very simple power system

Ø  Two generators one grounded through a reactor and one through a resister connected to a bus and through a step up transformer to a transmission lines

Ø  Another generator grounded a reactor is connected a bus and through a transformer to the opposite end of the transmission line

Ø  A load is connected to each bus

Ø  On the diagram information about the loads the ratings of the generators and transformers and reactance of different components of the circuit is often given

Ø  It is important to know the location of points where a system is connected to ground to calculate the amount of current flowing when an unsymmetrical fault involving ground occur

Equivalent circuit for various power system components:

(i). Generators

(ii). Transmission lines

(iii). Transformer

(iv). Static load

(v). Rotating load (motor)