What are the difference between Single Line Diagram (SLD ) and Three Line Diagram


Single Line Diagram Vs Three Line Diagram

A) Single Line Diagram (SLD)

1.Single line diagrams provide a basic road-map to the interconnections of the electrical system and serve as a building block from which all types of systems analyses are based.

2.SLD is a part of initial part of electrical design

3.SLD is mainly used for working out panel schedules,load schedules,fault analysis,protection system design.

4.A single line diagram is a simplified notation for representing a three-phase power system.Since the loads on three phase are identical,any one phase can be used for representing either of the phases.

B) Three-Line Diagram

1.Three-line diagram are prepared as a result of further working on the basis of a SLD as they provide details for electrical wiring connections.

2.Three-Line diagram is a part of the detailed design document.

3.Used for control designing circuit diagrams,control circuit,phase sequencing,differential relay setting,metering transformer connection.

4.Here all three conductors of the three phase systems are shown individually.Details of the power and the control circuits are also shown as per actual field connection.