SUBSTATION LAYOUT

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 acquiredCivil worksElectrical worksRoads 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 equipmentDistance between various equipmentsPhase segregation distancePhase 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)

Work section (open type switchgear)

• It should be capable of delimitation by screens or other means of restricting access to live conductors

• Any convenient sub division of a switching station that include one or more items of equipment

Busbar material

• Bus bar conductor• Post type insulators• Suspension insulator strings• Terminal connectors, clamps, tees, etc

Substation – Detailed Engineering

Electrical Protection and Metering SLD Substation Layout Plan and

Sections 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 StructuralFoundation Design and EngineeringStructure Design and EngineeringControl Room Building Design and EngineeringLightning & Lighting MastFoundation and Cable Trench LayoutStorm Water Drainage SystemRoad, Drain, Duct BankTransformer and Reactor FoundationTransformer Fire Wall and Soak PitProject Bill Of Materials

Detailed enginneringSystem 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 DevelopmentSite Selection through Distribution PlanningStudiesSelection of schemesLayout ConfigurationPermits and Approvals

Project EngineeringBasic and Conceptual EngineeringEngineering SpecificationsPreparation of Tender DocumentBid Evaluation / RecommendationsPost Contract Engineering / Review and Approval of Vendor DocumentsDetailed Design and Drawings

Project ManagementProject Scheduling and ControlProgress Monitoring and Co-ordinationInspection and Expediting

Site ServicesSupervision of Construction and ErectionProtection co-ordination and relay settingTesting and CommissioningPreparation of O & M ManualsAs-Built drawingsQuality Control ImplementationMeasurement 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 topressure and temperatures higher than ambient; ande. Insets, where necessary, to ensure every item of the assembly is clearly shown.Requirements of Shop Drawings• Detailed shop drawings shall be prepared covering all aspects of the works.• The Designer shall review the shop drawings and any other technical

submissions• 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 systemsshowing cable types and system components; andf. Block cabling diagrams

As-Constructed DrawingsProvide “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 terminationdiagrams;c. General arrangement drawings showing details of all equipmentinstalled; andd. 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

Manuals.System DrawingsThe 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 requirementsa. Base HV single line diagram;b. Base HV geographic layouts;c. Substation/switching station schematics for all effected substations andswitching stations;d. HV switchboards schematics for the main high voltage nodes such asCEPS and ISS, ande. 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