Substation Layout Design & Considerations

SUBSTATION LAYOUT
Design and considerations

Layout diagram
After bus arrangement is decided,
Key diagram and then layout drawing should be
prepared- to show actual position of each
equipment
Land plan- boundaries of the land acquired
Civil works
Electrical works
Roads and paths for the movement of men and
material

Electrical works
•For placing the various equipment in the
switchyard.
•The no. of columns and beams to support the
busbars and incoming and outgoing connections
depends upon the system voltage.
•It should reveals
Physical position of each equipment
Distance between various equipments
Phase segregation distance
Phase to ground clearance

Erection
•In electrical layout, overhead wire (for protecting
against lightning strokes) will be marked. O/H wire
decides no. of columns and beams by the structural
engineer.
•Steel erection key- determines no. of various structures
to be fabricated and helps the field erectors to erect
the various structures at right positions.
•No. of supporting structures (Las, Pts, CTs, CBs,
Insulators, etc) should be finalized from the drawing
•Supporting structures, columns and beams may be of
steel or reinforced cement concrete.

Clearances
Various clearances for different voltages
T o ensure satisfactory performance in service
Safety of personnel in inspection, operation and maintenance work
Electrical clearance
Earth clearance
Phase clearance (flash over)
Section clearance-safety clearance to conductors (min distance bt
unscreened live wires and work section. When screens are
interposed, the distance is to be taken as a taut string measurement
around the edge of the screen)
Ground clearance- safety clearance to insulators (min distance bt
insulators and work section)