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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
Land plan- boundaries of the land acquired
 Civil works
 Electrical works
 Roads and paths for the movement of men and
Electrical works
• For placing the various equipment in the
• 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
• 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
• 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.
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)
Work section (open type switchgear)
• It should be capable of delimitation by screens
or other means of restricting access to live
• Any convenient sub division of a switching
station that include one or more items of
Busbar material
Bus bar conductor
Post type insulators
Suspension insulator strings
Terminal connectors, clamps, tees, etc
Substation – Detailed Engineering
 Protection and Metering SLD
 Substation Layout Plan and
 Substation Clearance Diagram
 Erection Key Diagram
 Earthing & Lightning Protection
 Lighting System Design
 Cable Routing and Schedule
 Control Room Equipment Layout
 Battery and LVAC System
 SCADA System
 Project Bill Of Materials
Civil and Structural
Foundation Design and Engineering
Structure Design and Engineering
Control Room Building Design and
Lightning & Lighting Mast
Foundation and Cable Trench Layout
Storm Water Drainage System
Road, Drain, Duct Bank
Transformer and Reactor Foundation
Transformer Fire Wall and Soak Pit
Project Bill Of Materials
Detailed enginnering
System Studies and Reports
• Data Collection
• Power System studies for
network expansion
• Techno Economic
Feasibility Studies
• Detailed Project Reports
in WB/ADB format
• Financial Analysis
• Year wise
Implementation Schedule
Project Management
Project Scheduling and
Progress Monitoring
and Co-ordination
Inspection and
Project Development
Site Selection
through Distribution
Selection of schemes
Layout Configuration
Permits and
Project Engineering
Basic and Conceptual
Engineering Specifications
Preparation of Tender
Bid Evaluation /
Post Contract Engineering /
Review and Approval of Vendor
Detailed Design and Drawings
Site Services
Supervision of Construction and Erection
Protection co-ordination and relay setting
Testing and Commissioning
Preparation of O & M Manuals
As-Built drawings
Quality Control Implementation
Measurement and Certification
Procedure for drawing
General Drawings
Drawings of electrical plant and machines shall include, where appropriate:
a. Overall dimensions;
b. Terminal point details;
c. Minimum clearances;
d. Design pressures and temperatures for plant or plant items subject to
pressure and temperatures higher than ambient; and
e. Insets, where necessary, to ensure every item of the assembly is clearly
Requirements of Shop Drawings
• Detailed shop drawings shall be prepared covering all aspects of the
• The Designer shall review the shop drawings and any other technical
• to ensure that the proposed works comply with the design intent.
Electrical Drawings
• Electrical drawings for the installation shall be drafted in accordance with
AS 1102 and shall include the following:
a. Single Line Diagrams showing:
− Bus rating and switchboard characteristics;
− Current transformer ratios;
− Circuit breaker and fuse current ratings; and
− Ratings of capacitors, resistors and any other electrical devices.
− Items shall be designated as per AS 3702;
b. Substation Layout drawing to scale;
c. Site Layout drawings to scale;
d. Cable schedules (if required);
e. Overall system diagrams, for communication and control systems
showing cable types and system components; and
f. Block cabling diagrams
As-Constructed Drawings
Provide “As Constructed” drawings that show as a minimum:
a. The final locations of cables, pits, cable joints etc;
b. Wiring diagrams for all equipment installed including termination
c. General arrangement drawings showing details of all equipment
installed; and
d. Any information as required facilitating operation and maintenance of the equipment.
e. The “As Constructed” drawings shall form the basis of the Operations and Maintenance
System Drawings
The designer shall prepare revised system documentation whenever an alteration is preformed to
the reticulation system or a new system is installed.
As a minimum the following documentation shall be provided in suitable hard copy and digital
format in accordance with the Defence requirements
a. Base HV single line diagram;
b. Base HV geographic layouts;
c. Substation/switching station schematics for all effected substations and
switching stations;
d. HV switchboards schematics for the main high voltage nodes such as
CEPS and ISS, and
e. LV distribution pillar schematics.
Key diagram of 11kv substation
Key diagram for 33kv substation
Key diagram of 66kv substation
Key diagram for protection
Key diagram for indoor substation
Reuse of scrap material