National Seminar on New Generation High Performance Conductors 4 th Dec’14
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National Seminar
on
New Generation High Performance Conductors
4th Dec’14
Compulsion for alternative – why?
___________________________________
New line ROW Constraint
Increasing urbanization left no inlet for critical S/S.
EHV Cable cost still very high
Use efficient
conductor from day one
Existing line (Overloaded/ Uprate the capacity)
Replace/ Reconductoring with efficient conductor
Limitation of power flow
What is efficient Conductor ?
ATTRIBUTES WHY
1) More current carrying capacity More power
2) High Conductivity
(Low Resistance)
Efficient power transfer
3) Temperature rise with current More I2R loss
4) Ultimate Tensile Strength Sag Tension compliance
5) Co-efficient of linear expansion
limit
Sag for ground
clearance as per IE rules
6) Weight per meter Optimal loads for tower
design
7) Cost Conductor contributes
40% of line cost
What GETCO is doing for new lines ?
Options of conductor Benefits / Short comings Category Cost factor
1) ACSR Zebra
(220 kV)
Presently used Moderate Temp. Comparatively
Low
2) ACSR Moose
(400 kV)
Presently used Moderate Temp. Comparatively
Low
3) AAAC Lower weight, Higher Sag,
Higher Resistance
Moderately Higher
Temp. (90 ⁰C)
Marginally High
4) TACSR / ZTACSR Higher Sag, Higher
Resistance
Higher Temperature
(150-210 ⁰C)
High
5) ACSS Higher Sag, Higher
Resistance
Higher Temperature
(250 ⁰C)
High
6) AL59 Higher Sag, Lower
Resistance, Lower weight
Moderately Higher
Temp. (95 ⁰C)
Marginally High
7) CCC Lower Sag, Lower
Resistance, Special T&P
HTLS (180 ⁰C) Very High
8) Invar type Lower Sag, Higher
Resistance
HTLS (230 ⁰C) Very High
9) GAP type Lower Sag, Higher
Resistance, Special T&P
HTLS (150-210 ⁰C) High
Characteristics of various options:
What GETCO is doing for new lines ?
• Adopted for 220 kV & 400 kV new lines.
• Options Available
1) Equal Diameter to ACSR
2) Equal Weight to ACSR
• Adopted - Equal Weight to ACSR Zebra
(220 kV)
- Equal Diameter to ACSR Moose
(400 kV)
What GETCO is doing for new lines?
(220 kV) Factors considered for decision making :
1) Current capacity required – 170 to 200% of ACSR conductor
2) Project time – Use of existing tower design, since new takes time.
3) Efficiency – I2R loss
4) Satisfy Sag-Tension requirement with existing Tower Spotting Data
5) Dependency on supplier for hardware & accessories suitable for high temperature
6) Competency and T&P to handle erection of new conductor
7) Project cost (Deciding factor)
What GETCO is doing for new lines? (220 kV)
Factors AL59 suitability
Current capacity requirement Doubled with moderate
Temperature rise (95 ⁰C)
Project time Suited to existing tower
design
Efficiency Low I2R losses even@ 95⁰C
Satisfy Sag-Tension with existing
Tower Spotting Data
Satisfied with 3 meter
extension and by limiting the
wind span
Dependency for Hardware &
Accessories
Adequate Indigenous
manufacturers
Competency of erection Does not require special
skill or T&P
Project cost Increases by 10% appx.
How AL59 suited for decision making:
What GETCO is doing for new lines ? (220 kV)
PARAMETER AL59 (equal
diameter to
ACSR Zebra)
AL59 (equal
weight to ACSR
Zebra)
1) Type 61/3.18 61/3.50
2) Diameter (mm.) 28.62 31.50
3) Weight (kgs./km.) 1336 1618
4) Cross section area (sq. mm.)
484 587
5) Resistance (Rdc @ 20 0c) (ohms/km.)
0.06250 0.05070
6) UTS (KN) 121 141
7) Wind Span (meters) 385 350
8) Ampere Capacity 900 1030
Comparison of options:
What GETCO is doing for new lines? (220 kV)
PARAMETER ACSR Zebra AL59 (equal
weight to ACSR
Zebra)
1) Resistance (Rdc @ 20 0c) (ohms/km.)
0.06869
0.05070
2) A.C. Resistance (@
maximum operating Temp.)
0.08487
@670c
0.06855
@950c
3) Ampere Capacity (AT –
40 0c)
500 1030
4) Power Transfer capability
in MW @ p.f. 0.95 per ckt.
181 MW 373 MW
5) Net Power Transfer for
100 km. line
175 MW 350 MW
Ultimate comparison with ACSR Zebra:
What GETCO is doing for new lines ?
(220 kV)
• Options to counter higher sag at full temperature (950c),
1) Reduction of Normal span
2) Use of extension permanently
• Practice adopted by GETCO
1) Use of extension permanently –
lesser cost & additional margin
available for ground clearance.
2) Reduction in Maximum wind span to
attend wind load increased due to
diameter increase.
Changes adopted to satisfy Tower Spotting Data:
PROJECT COST (220 kV)
ACSR Zebra
conductor
AL59 with
+3 meter
extension
AL59 with
reduced normal
span
Project Cost 100 110.2% 111.20%
What GETCO is doing for new lines ?
(220 kV)
Conclusion:
• Double the Ampere Capacity & Net power transfer capacity by addition of appx. 10% to project cost and without operating line at excessive higher temperature .
• Low resistance compared to ACSR Zebra even at rated Temperature results in to lower loss for same power transfer & do not aggravate % Voltage Regulation.
• No special erection methodology, special tools tackles, special design Hardwares & Accessories required.
• Indigenous supply available for conductor and hardwares.
What GETCO is doing for new lines ?
(400 kV)
• Adopted AL59 for 400 kV New Lines.
• Options Available
1) Equal Diameter to ACSR Moose
2) Equal Weight to ACSR Moose
• Adopted - Equal Diameter to ACSR Moose.
What GETCO is doing for new lines ?
(400 kV)
PARAMETER AL59 (equal
diameter to
ACSR Moose)
AL59 (equal
weight to ACSR
Moose)
1) Type 61/3.50 61/3.89
2) Diameter (mm.) 31.50 35.01
3) Weight (kgs./km.) 1618 2000
4) Cross section area(mm2) 587 725
5) Resistance (Rdc @
200c) (ohms/km.)
0.05070 0.04095
6) UTS (KN) 141 174
7) Ruling Span(Sag-Tension) 370 363
8) Wind Span 400 363
Comparison among options:
What GETCO is doing for new lines?
(400 kV)
PARAMETER ACSR Moose AL59 (equal
diameter)
1) Resistance (Rdc @ 20 0c)
(ohms/km.)
0.05596
0.05070
2) A.C. Resistance (@ maximum
operating Temp.)
0.0722 @800c 0.06855 @950c
3) Ampere Capacity (AT – 40 0c) 790 1030
(130% higher)
4) Thermal Power Transfer capability
in MW per ckt.
(p.f. 0.95, factor 0.9)
936 MW 1220 MW
(130% higher)
6) Project Cost 100% 106 -108%
Ultimate comparison with ACSR Moose:
What GETCO is doing for new lines? (400 kV)
Factors AL59 suitability
Current capacity requirement Increased 30% with moderate
Temperature rise (95 ⁰C)
Project time Suited to existing tower design
Efficiency Low I2R losses
Satisfy Sag-Tension with
existing Tower Spotting Data
Satisfied with normal tower and
by limiting the ruling span
matching with actual field
observation
Dependency for Hardware &
Accessories
Adequate Indigenous
manufacturers
Competency of erection Does not require special skill or
T&P
Project cost Increases by 6-8% appx.
How AL59 suited for decision making:
What GETCO is doing for new lines ?
(400 kV)
• Thermal capacity increased by 30% at increase of project cost 6-8%
• As the Sag at maximum operating temperature is increased, ruling span is reduced by appx. 7%.
• By retaining wind and weight span additional benefit of reduction in vertical load & longitudinal load added FOS for existing tower design .
CONDUCTOR COST
Conductor Cost
(Lac Rs./km.)
Comparison
ACSR Zebra 2.265 **
ACSR Moose 2.827 **
AL59 (61/3.50) 2.952 130% of Zebra
104.5% of Moose
GETCO Expectations
• Indigenous manufacturers – conductor,
hardware
• Availability of erection agencies
• Indigenous testing agencies
• Innovative erection technology e.g. live
line
• Optimum cost
Thank You
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