Successful Implementation of GIS Techniques for

Route Alignment & Surveys of Power Transmission Projects

of POWERGRID

Power Grid Corporation Of India Ltd

To optimize cost of transmission line

Line length, number of locations, deviations Minimum river crossings Minimum forest areas Accessibility, right of way considerations To assess route constraints and do construction planning

To ensure statutory clearances

Ground clearance Horizontal/Right of way clearance Clearances from power lines, railway lines, road crossings etc.

Why Surveying Is Important ?

UHV Transmission Lines UHV Transmission Lines - 765 kV , Requiring Large ROW - 765 kV , Requiring Large ROW

Long Distance Transmission Long Distance Transmission Lines – 500 kV HVDCLines – 500 kV HVDC

Transmission Lines Transmission Lines thru’ Agricultural fieldsthru’ Agricultural fields

Transmission Lines in Hilly areasTransmission Lines in Hilly areas

Multiple Transmission Lines Through Same Corridor

Transmission Line River CrossingsTransmission Line River Crossings

Project Conceptualization / Project Feasibility StageFaster and accurate techniques required to evaluate various line routes

Pre-Construction StageRoute alignment, Detailed Mapping of right of way, ground profiling, finalisation of tower locations with geo technical detailsDetailed contouring of undulated terrain for estimation of benching and revetment quantities

Project Construction StageCheck Survey only

Transmission Line Surveying

Large Quantity variations during execution stage avoided Constraints assessed in advance Engineering activities can be taken in advance Construction work can be taken up immediately after

contract award Reduction in IDC due to reduction in project execution time – offsetting cost of survey using modern techniques Reduction of even 1-2 kms line length would offset

cost of surveying using modern techniques

Advantages of Conducting Detailed Survey in Advance

Detailed Survey – Modern TechniquesDetailed Survey – Modern Techniques

Route Alignment using latest satellite Route Alignment using latest satellite imageries (PAN + LISS III Merged imageries (PAN + LISS III Merged products) superimposed on Survey of products) superimposed on Survey of India Topographical MapsIndia Topographical Maps

Digital terrain modeling in hilly terrain Digital terrain modeling in hilly terrain using contouring datausing contouring data

Detailed Survey using GPS, Total stations Detailed Survey using GPS, Total stations or alternatively ALTMor alternatively ALTM

Digitized contouring at undulated / hilly Digitized contouring at undulated / hilly tower locationstower locations

Identification of Route constraints,Identification of Route constraints, Identification of infrastructure details Identification of infrastructure details

Detailed Survey – Modern Detailed Survey – Modern TechniquesTechniques

Tower spotting & optimization of Tower spotting & optimization of locations using commercial software locations using commercial software like PLS CADDlike PLS CADD

Estimation Of BOQEstimation Of BOQ Preparation Of Survey reportsPreparation Of Survey reports Soil InvestigationSoil Investigation

METHODOLOGY

Acquisition of Remote Sensing Data

Digitization of Base details from SOI

sheets

Preparation of Updated Digitized Maps

Selection of corridors/alternatives

Route Selection Reconnaissance Survey

GPS/Total Station Survey

Digitized Profiling

Computer-aided tower spotting

BOQ Estimation, Reports etc.

Geotechnical Investigations

Digitized ToposheetDigitized Toposheet

Survey of India Topo Sheet Corresponding Digitized Map indicating relevant information

Digitized Satellite ImageDigitized Satellite Image

Satellite Imagery (5.8/20 m resolution)

Corresponding Digitized Image indicating relevant information

Selection of Alternative RoutesSelection of Alternative Routes

Bee Line

Existing Line

Alternative 3

Alternative 2

Alternative 1

Computerized Route Optimization by Study Computerized Route Optimization by Study of Alternative Routesof Alternative Routes

Bee Line

Existing Line

Alternative 3

Alternative 2

Alternative 1

Digital Terrain ModelDigital Terrain Model

Computerized Three Dimensional Image

Bee Line Alternative-3Alternative-1

Alternative-2

Advantages of Modern Advantages of Modern Survey Techniques over Survey Techniques over

Traditional survey MethodTraditional survey Method

Topographic Sheet – Indicates only Nala

Satellite Image – Indicates Large waterbody

Topographic Sheet – Indicates only a part of Canal

Satellite Image – Indicates Another Branch of Canal

Topographic Sheet – Not many details

Satellite Image – Indicates Recent Infrastructure Developments, Landslide Areas

Transmission Line Survey through GIS

Change of River Course

Detailed Survey on Selected RouteDetailed Survey on Selected Route

Detailed Survey is done on the selected route using Total Stations.

Plotting of Surveyed Route on the Topographical Maps

Tower Spotting and profiling is done using PLS-CADD Software.

PLS CADD Software PLS CADD Software

Power Line Systems Computer Aided Design and Drafting (PLS CADD) is a software developed by Power line systems Inc. USA.

The software is used for Tower Spotting.

The software automatically provide SAG Clearances.

The software automatically calculates wind & Weight Span.

The software prepares the “Plan & Profile View” of the T/L line.

Report Generation.

The overall organization of the PLS CADD software is shown in the following slide.

PLS CADD SoftwarePLS CADD Software

3-D Model of3-D Model ofLine in CorridorLine in Corridor

3-D Terrain3-D Terrain

Survey DataSurvey DataFeature CodesFeature Codes

Design CriteriaDesign Criteria

LoadsLoadsClearancesClearances

StructuresStructures

GeometryGeometryStrengthStrength

CablesCables

All PropertiesAll Properties

ReportsReportsMaterial ListMaterial ListSpecificationSpecification

Etc.Etc.

DrawingsDrawingsPlan & ProfilePlan & ProfileExported toExported toCAD systemCAD system

ArchivingArchivingLineLine

ManagementManagement

FutureFutureModificationsModifications

Corridor TerrainCorridor Terrain

Ground + ObstaclesGround + Obstacles

InstallationInstallationSpottingSpotting

AutomaticAutomaticManualManual

StringingStringingSaggingSagging

Etc.Etc.

CalculationsCalculations

Sag TensionSag TensionClearancesClearances

Struct-StrengthStruct-StrengthSwingsSwings

Etc.Etc.

LibrariesLibraries

InputInput ProcessingProcessing OutputOutput

Plan & Profile DrawingPlan & Profile Drawing

Key AdvantagesKey Advantages

PLS Cadd – software used for PLS Cadd – software used for preparing “Plan & Profile Drawing” preparing “Plan & Profile Drawing” and “Report Generation”and “Report Generation”

Eliminates manual error in Report Eliminates manual error in Report generation.generation.

Empowers Managers to move / modify Empowers Managers to move / modify structures and see the effect on the structures and see the effect on the Line.Line.

Reports / Calculations of modified Reports / Calculations of modified structures can be viewed instantly. structures can be viewed instantly.

Airborne Laser Terrain Mapping(ALTM)

First reflection(first pulse)

Last reflection(last pulse)

The laser locator installed onboard records both returns from the vegetation cover and objects on the ground (that is the first pulse) and from the terrain under the vegetation (that is the last pulse). This system together with data processing software are used to create digital terrain model not affected by the vegetation.

New Line ConstructionNew Line Construction

Knowing exact geometry along the route with as many details desirable as it makes design process much more productive. With laser survey much more efficient and fast to collect the information along the route for new power line design and construction.

Evaluation Of ClearancesEvaluation Of Clearances

Thermal Uprate StudiesThermal Uprate Studies

Thermal uprate study will become much less complicated process with laser survey data. Three-dimensional information about actual power line geometry and condition brings all relevant details along the route of the power line.

TEESTA-V (Route Alignment using satellite imagery) SRINAGAR-LEH (Route Alignment using satellite imagery) PARBATI-II, KOLDAM KAHALGAON BARH KUDAMKULAM NEYVELI RANCHI-SIPAT RAPP-5&6 MAITHON WR STRENGTHENING PARBATI-III URI-II etc. etc.

DETAILED SURVEY USING MODERN TECHNIQUESFOR PROJECTS

– COMPLETED / UNDER IMPLEMENTATION

Thank You