Overview & Need for HTLS Conductor

8/11/2019 Overview & Need for HTLS Conductor

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Overview & Need of HTLS Conductors forTransmission Network

Overview & Need of HTLS Conductors forTransmission Network

BY:Mata PrasadFNAE


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Role of Electricity

Electricity - A vital Part of daily life

Electricity taken for granted

Complete darkness without

Electricity in life.

No Electricity Life comes to a

Standstill.

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Constraints in the Indian Power Sector

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Cateringto present

loaddemand

Reliabilityof Existing

Lines

ROW

Economics

Erection ofNew Lines

Loading ofExisting

lines


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Solutions to the Constraints of IndianPower Sector

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Re-Tensioning of Old Lines

Re-Conductoring of lines with high loadability limitsover existing Towers

Intelligent Solutions for Optimal use of Existing ROW

Use of High Ampacity, Low sag Conductors HTLSTechnology


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Need of HTLS Conductors

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Overloading of Power Network lead to the evolution of new high

Ampacity conductors

Conductor manufacturing companies in Canada, Japan, Europe & USA

explored the invention of high ampacity conductors

Introduction of High Temperature Low-Loss & Sag Conductors in 1970-

75 at Japan

Application of HTLS conductors :Re-Tensioning Lines with increased Sag due to Cyclic Loading

Re-Conductoring - Same Voltage level & Tower Profile

Green Field Projects Increased Loadability


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HTLS Conductors Group

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HTLS

Gap TypeConductors

Invar TypeConductors

CompositeCarbon Coreconductors

ACSS/TW


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ACSS Type Conductors

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Construction:- Core made up of Galfan Coated Steel wire/Al. Clad Steel wire/- Outer Layer Comprises of 1350 Annealed Aluminium Wires

Features:- Suitable for re-conductoring & new line solutions- Ampacity of the line gets enhanced- No Modifications or extension of tower required- Low Co-efficient of Thermal Expansion- Operating Temperatures up to 250 Deg C- High strength steel core carries load, hence Low Sag- Increased Conductivity 63% (IACS)- Low losses- Better Self Damping Characteristics


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Gap Type Conductors

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Construction:- Core made up of Galfan Steel or high Strength Galvanized Steel- Outer layer formed of concentric layers of Super Thermal Resistant

Trapezoidal Aluminium Alloy Strands- Gap filled with Grease

Features:- Low Co-efficient of Thermal Expansion- Operating Temperatures up to 200 Deg C- Conductor strung by tensioning steel core, Hence low sag

- Line capacity can be increased by 50% to 100%- Excellent Solution for reconductoring


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INVAR Type Conductors

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Construction:- Core made up of Iron (36% Ni in steel) Nickel alloy- Outer layer formed of concentric layers of aluminium Strands of

thermal resistant aluminium alloy (with Zirconium)

Features:- Most preferred for re-conductoring solutions- Ampacity of the line gets enhanced

- No Modifications or extension of tower required- Low Co-efficient of Thermal Expansion- Operating Temperatures up to 200-230 Deg C- Low sag compared to conventional ACSR


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Carbon Composite Conductors

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Construction:- Core made of High Strength glass fiber & Composite carbon- Outer layer formed of trapezoidal shaped aluminium strands

Features:- High Ampacity low loss Hybrid Conductors- Resistant to environment degradation- Reduce line losses up to 40%- 28% more quantum of aluminium- 25% stronger & 60% lighter steel core, hence

fewer or lower towers- Operation temperature up to 180 Deg C- Less Coefficient of Thermal Expansion- Hence Low sag at high temperatures- Best suitable for re-conductoring & New line applications


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High strength toweight ratio

Reduced Sag

Lowest coefficient ofthermal expansion

Improved Self-Dampingcharacteristics

Resistant to AeolianVibration

Lowest possibleelectrical resistance

Greater conductivity

Rated Max. Cont.Operating Temp.

1800C

Reduced LineLosses

Lower OverallLifecycle Costs

Increased ElectricalCapacity

Decreased StructuralCost

23 January 2014 11

Composite CarbonCore Conductor


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23 January 201412

Comparison Between Temperature & Sag

Composite Carbon Core Conductor ExceptionalHigh Temperature, Low Sag Capability


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23 January 201413

Lower I 2R Power Losses

Composite Carbon Core Conductor hasLowest I 2R Power LossesComposite Carbon Core Conductor greateraluminum content enables higherconductivity and lower resistance properties,lowering I 2R power losses.


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Concept of Uprating of Existing Lines

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Alternatives considered for increasing the Ampacity of Old lines:Re-tensioning of old lines with certain limitationsReplacing Old Conductor by HTLSAdding new circuit with conventional conductors of higher sizes or withHTLSAdding higher Capacity Conductor depending upon the strength of towers

Optimum solution for uprating depends upon :Cost EconomicsEase of stringing in hot line or live line conditionsIn case of D/C line, reconductoring could be done with shut down of onecircuit & the second circuit continues to supply the load

The main purpose of HTLS Conductors is to enhance & improve thethermal rating of a transmission line & at the same time ensure thestability being kept within limits.


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Advantages of Uprating/Reconductoring withHTLS Conductors

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Increased loadability such that the lines will no longer be thermallylimited.Proper Correction through effective reactive compensation to avoiddepressed voltage dip.Even though the loadability of line be increased by two times, theprobability of load throw-off from the line due to outage or anyreason, would require the remaining transmission lines in the

network to withstand the loss of the line with HTLS Conductors.N-1 & N-2 Contingencies are comfortably met with the use of HTLSConductors when the adjacent lines are out.


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Twin Bundle Conventional Conductor v/s

Single HTLS ConductorComparison Sheet of Moose ACSR v/s HTLSequivalent Moose Options

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Role of Reactive Power Support for

Uprating Projects

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Reactive Power Consumption would increase to four times inHTLS line of more than 200 Km.Cost of Provision of additional Reactive Power must beevaluated while adopting HTLS conductors.For longer lines more than 300 kms, unswitched shunt reactorsare applied which brings own the SIL limit of the line to about70 %.SIL PPT Slides.


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Graphical Representation of Resistance,Reactance and Impedance of conventional ACSR

Moose Conductor and other HTLS option

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

ACSR TACSR ACSS/TW Invar Type Gap Type Composite Core Type

Resistance, R Reactance, XL-XC Impedance,Z Impedance,Z (Represented through line)

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Presence of HTLS Culture in India

Strengthening of Transmission systemwith 220 kV line with INVAR ConductorPGCIL, Gurgaon

132 kV Pirana ISRO Sabarmati Lineat Ahmedabad with Gap ConductorTorrent Power

Multi Circuit Portion of 400 kV Gaya Maithon / Koderma - Gaya LinePGCIL

Reconductoring 37 kms of 132 kV linewith ACCC CasablancaOPTCL, Bhubaneswar, Odisha

132 kV Vinzol Pirana Line with ACCCConductorTorrent Power

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Coordination of HTLS Lines whenconnected to Substations

Large , Bulky & heavy H/W of HTLSIf 220 kV bus bars are rated for say 1600 amperesthen the placement of transformer bays vis-a- vis theline bays alternately dispersed could decide as tohow much power can be allowed to flow over thebus bars depending upon the diversity.

This could be quite crucial as switchgear equipmentare normally rated for normal current of 1600 Ampsand short circuit rating of 40 KA for new substationswhile bus bars should be much higher with at least25% margin.


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Potential Projects for Uprating

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Short Overloaded inter-state, inter/intra regional linesRing Mains around Metropolitan CitiesConversion of Quad Bundle AC Lines to Twin Bundle Lines with HTLSUprating of 132 kV & 220 kV Grid radial & Grid Connected lines toincrease Ampacity so as to meet the growing demandUsing Bundled HTLS Conductors on HVDC Lines can be moreeconomical due to reduced lossesOptimizing the diameter & cross section of HTLS Conductors with aview to optimize the Voltage Gradient & to access the coronaStudies of Life Cycle Costs & Cost Benefit Analysis for HTLS Pay Backperiod of 10 years shall be considered attractive400 kV & 220 kV Lines commissioned before 1980 by State & CentralSector need to be examined for switching over to HTLSInnumerable Lines under Private Sector which could be the potentialcandidates for HTLS


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Acknowledgement The paper has drawn information from publishedliterature, technical deliberations with the experts inIEEE, IEE, EPRI, CTC, J-Power and many other foreignresources and above all from APAR , Sterlite , Torrent, TataPower, PGCIL and persuasion as also support from Mr.Chaitanya Desai of APAR are acknowledged withgratitude.The encouragement and support from Mr. Rajesh Jain, Shailesh Jain and Mr. Deepak Khandelwal has beenvery timely and effective.

The paper has drawn information from publishedliterature, technical deliberations with the experts inIEEE, IEE, EPRI, CTC, J-Power and many other foreignresources and above all from APAR , Sterlite , Torrent, TataPower, PGCIL and persuasion as also support from Mr.Chaitanya Desai of APAR are acknowledged withgratitude.The encouragement and support from Mr. Rajesh Jain, Shailesh Jain and Mr. Deepak Khandelwal has beenvery timely and effective.


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Conclusion

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Uprating & increasing the Ampacities of the lines in the existing ROW must be taken up.

It is proposed to create a High Power Working Group Consisting of CEA Members, Central & State Utilities, Members from PrivateSector, Consultants and professionals from IITs to study the technical feasibilities of projects including the life cycle costs and cost benefitanalysis & also to identify the probable Potential Projects of Uprating the Ampacities & frame the time schedule.

Uprating & increasing the Ampacities of the lines in the existing ROW must be taken up.

It is proposed to create a High Power Working Group Consisting of CEA Members, Central & State Utilities, Members from PrivateSector, Consultants and professionals from IITs to study the technical feasibilities of projects including the life cycle costs and cost benefitanalysis & also to identify the probable Potential Projects of Uprating the Ampacities & frame the time schedule.


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1/23/201424

Thank YouThank You

Overview & Need for HTLS Conductor

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