# Single line diagram

May 14 • Notes • 8442 Views • 3 Comments on Single line diagram

Single line diagram

As per the definition of the single line diagram, it is specified as the diagram that uses single line and symbols to represent the path and the components of an electrical circuit. These diagrams are specifically use when the information about the circuit is required but the details of the actual wire connection and the operation of the circuit are not needed. The entire logic of an electrical circuit or one can say it as a system using standard symbols are properly specified diagram. In other words we can say that the proper relationship between the circuit and the component are provided but the actual location of the component not needed. The single diagram provides an easy and understanding of the connection and the component.

Importance 0f single line diagram

1. Identification of the problem location, in safety conformity and the staff safety can be benefited by the use of single line diagram.

2. If in any case the inaccuracy in the connection and the failure arises the updation of the single diagram becomes easy even on the regular basis.

3. The information from one line diagram can be widely used to enhance the performance of service activities.

4. The single line diagram can be termed as building an electrical system.

Construction of single line diagram

1. As we know that the single line diagram is a simplified way for representing a 3 phase power system, so in case of representing each of the 3 phases with a separate terminal only one conductor is used to represent it.

2. The electrical elements like transformer, capacitor, circuit breaker, bus bars are represented by the standard schematic symbols.

3. It is to be noted that the elements portrait on the diagram doesnot represent actual physical size of the electrical component.

4. The component of the diagram are arranged in the order of the decreasing voltage level i.e the component with the highest voltage is present at the top right of the diagram and hence forth.

Steps required for the construction of single line diagram

1. Preliminary one line diagram.

2. Partially developed diagram.

3. Developed diagram.

1. Preliminary one line diagram

Under this stage the following points must be kept in mind.

a. The major component rating and the system voltage has to be specified.

b. The sizes construction of the medium voltage cables must be properly shown.

c. The number and the rating of all the motors should be properly shown.

d. The available supply system short circuit capability should be represented either in the symmetrical MVA ( X/R ratio) or as per unit (R+jX).

2. Partially developed diagram

a. In this stage the results of short circuit calculations are shown using the selected circuit breaker rating.

b. The CT ratio is selected for considering the maximum transformer rating and the motor rating.

c. The CT and PT are properly located considering the type of protective relaying.

3. Developed diagram.

Under this stage

a. All the metering , relaying and the instrumentation must be properly shown.

b. Further from these compnent proper specified component must be selected.

1. List the type of electrical diagram that any electrical engineer deals with?

Ans: 1. Block diagram,

2. Schematic diagram,

3. Pictorial diagram,

4. Wiring diagram,

5. Single line diagram.

2. Define single line diagram in a complete manner.

Ans: As per the definition of the single line diagram, it is specified as the diagram that uses single line and symbols to represent the path and the components of an electrical circuit. These diagram are specifically use when the information about the circuit is required but the details of the actual wire connection and the operation of the circuit are not needed. The entire logic of an electrical circuit or one can say it as a system using standard symbols are properly specified diagram.

3. What are the advantages of the single line diagram?

Ans: 1. Identification of the problem location, in safety conformity and the staff safety can be benefited by the use of single line diagram.

2. The single line diagram can be termed as building an electrical system.

4. As per IEEE and ANCI what are the steps that need to be followed for single line diagram?

Ans: 1. Preliminary one line diagram.

2. Partially developed diagram.

3. Developed diagram.

### 3 Responses to Single line diagram

1. Swathi says:

significance of single line diagram

2. Rachita Mishra says:

one-line diagram or single-line diagram is a simplified notation for representing a three-phase power system.The one-line diagram has its largest application in power flow studies. Have a look on it.

3. Shilpa Ranjan says:

This post explained about the single line diagram its importance and construction and many other. This is one of the important concept of engineering subject.This is a good short note on the given topic.This can be helpful !!