Stringing Methodologies of High Temperature Low Sag (HTLS) …ieema.org/wp-content/uploads/2015/05/LFE_KEC_-_New_Generation_High... · Silliguri-Purnea Re- conductoring Project –

KEC International Ltd.

Stringing Methodologies of High Temperature Low Sag (HTLS) Conductors

1 KEC International Ltd. 04/12/2014

Contents

Case Study – Siliguri – Purnea Re-conductoring project

Project scope, details and importance

Major points during planning and pre-execution

Installation Methodology

Man and Machine used

Special Tools and Hardware requirement

Major challenges faced during execution

Benefits and Advantages

Future prospects

2 KEC International Ltd.

04/12/2014

Silliguri-Purnea Re- conductoring Project – A Case Study


• Re - conductoring Package for 400KV D/C Silliguri - Purnea Transmission line associated with Eastern Region Strengthening scheme-I

Name

• Power Grid Corporation of India Limited

Client

• Supply and Re - conductoring of 173 Km 400KV Silliguri - Purnea D/C Line

Scope

• Gap conductor

Conductor Used

• 18 Months

Duration

Project scope

Increase Power flow Capacity of Siliguri - Purnea 400kV D/C Transmission Line

to two times of the existing line by re-conductoring

Increase of current carrying capacity of sub conductor from existing 614 Amps

to 1228 Amps

No modifications in structures and foundations

Circuit wise implementation by keeping the other circuit live

Time schedule equivalent to stringing of double circuit twin conductor line


Case Study – 400kV D/C Siliguri – Purnea Line


- Line length : 175kms

- Line passes through the

chicken neck area having

serious ROW constraints

- Vast Hydro potential in NER

to be accessed through this

corridor

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Power Through Siliguri – Purnea Twin Circuit ( Normal condition)


Yr.

2009

Yr. 2011

Yr. 2013

Yr. 2017

Net Power on AC system at Siliguri (MW) 3300 2975 2975 2975

Flow in 400kV D/c(quad)(MW) (55%) 1815 1636 1636 1636

Flow in 400kV D/c (twin)(MW) (45%) 1485 1339 1339 1339

Power/circuit in twin line(MW) 743 669 669 669

Current per conductor(kA) 0.54 0.48 0.48 0.48

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Power through Siliguri – Purnea Twin circuit (contingency condition)


2009 2011 2013 2017

One quad ckt. out

Pole Out Pole Out Pole Out

Net Power on AC system at Siliguri (MW) 3300 4325 5675 5675

Flow in 400kV Quad Line (MW) 1254 2379 3121 3121

Flow in 400kV Twin Line (MW) 2046 1946 2554 2554

Power/circuit in twin line(MW) 1023 973 1277 1277

Current per conductor(kA) 0.74 0.70 0.92 0.92

Outage of quad D/c

Pole + quad S/c

out

Pole + quad S/c

out

Pole + quad S/c

out

Flow in 400kV Quad Line(MW) (38%) - 1644 2157 2157

Flow in 400kV Twin Line(MW) (62%) 3300 2682 3519 3519

Power/ckt in twin line 1650 1341 1759 1759

Current per conductor(kA) 1.19 0.97 1.27 1.27 04/12/2014

Major Considerations during Planning

Brainstorming based on the detailed survey to be carried out

Limited period shutdown and ROW mitigation has to be planned well in advance

Detailed shut down plan to be prepared based on above

Strategy to address Incomplete or deformed existing Towers to be prepared

Variance in Spans as compared to Actual and approved Tower schedule to be studied

Ensure that T & P shall be in good condition so as to avoid breakdown during stringing

Arrangement of high precision and mechanized equipment to be arranged

Experienced and technically skilled work force to be arranged

Safety tools to be arranged


Installation Methodology of GAP conductor

• More or less Similar Installation method compared to conventional conductor

• At the moment of installation all the tension is applied on steel core on which a steel dead end clamp is compressed

• Aluminum part is left hanging on steel core as dead weight

• After an overnight settlement period, aluminum sleeves are compressed over the steel & conductor

• Line hardware & Insulator strings similar to the one used for conventional conductor with the exception of compression dead end clamp

• Up to 2 times the ampacity with the same existing tower design

• Above the stringing Temperature, thermal expansion characteristic is same as that of steel core, which allows small sag at higher temperature


Man and Machine

Sl. No Gang Type No. of Gangs Gang Strength Productivity

1 TSE gangs 3 60 8-10 Km/Gang/Month

2 Manual Stringing Gang 3 35 3-4 Km/Gang/Month

Special T&P requirement

• Compress type Stringing Clamp

• Come along Clamp

• Steel Come along Clamp

• Locking Clamp

• Sagging Platform


Special Tools & Tackles Required for Gap Conductor Stringing

KEC International Ltd. 11

Pulling Eye Conical Clamp

Steel Clamp Aluminium Cutter

Platform

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Installation activities of Gap Conductor

Damages and shortages

to be rectified

Scaffolding to protect ground infrastructure

Temporary reinforcement in case of higher

construction loading

De-clipping and Three sheave roller installation

Existing conductor is used for pulling new conductor


Sagging at Suspension Towers:

For longer sections we have to do sagging activity at suspension Tower with the

help of semi strain assemblies and Sagging Platform

For joining conductor, aluminium strings has to be pressed at sagging platform

which requires skilled labour and advance jointing machines

Precautions to be taken during stringing


Technical Benefits during Installation of GAP conductor


Excellent Sag properties not only compared to conventional conductors, but also amongst the HTLS conductors family.

04/12/2014

Learnings from the project

KEC International Ltd. 15

Not difficult to execute, same efforts as a normal conductoring job of Conventional Conductor

Only precision in handling of conductor is required

Special Tools and Plants require one time training for manpower

Initial execution takes time, but productivity improves with expertise and experience

Profitable compared to normal conductoring job with same resources applied

04/12/2014

Future Prospects of HTLS conductors

KEC International Ltd. 16 04/12/2014

KEC International has been recently awarded with the reconductoring

project of 132 kV Jeerat – Dharampur Line (8.2 Kms) & 132 kV Dharampur –

Titagarh Line (27.52 Kms) from WBSETCL

Based on our Learning's from previous projects, execution will be

completion within scheduled time frame

Many Existing Lines in India today facing a problem of over loading (28 lines

as per POSOCO data (2013) , approx. 2900kms of network) and increasing

Solution in hand – Big market potential for Re - conductoring projects

Increasing supplier base for HTLS conductors across world

THANK YOU

17

The secret of change is to focus all of your energy, not on fighting the old, but in building the new.

- Socrates

Vimal Gupta KEC International Limited

KEC International Ltd. 04/12/2014

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