identifying opportunities to improve the efficiency of power transmission through existing overhead...

Identifying opportunities to improve the efficiency of power transmission through

existing Overhead Power Lines

Konstantinos Kopsidas

Supergen - AMPerES

Structure of the PresentationStructure of the PresentationStructure of the PresentationStructure of the Presentation

Supergen - AMPerES

• Basics of Ampacity & Sag • Holistic Computational Methodology for

Rating an OHL• Analysis/Comparison of AAAC & ACSR

Conductors on an 33kV OHL system• Advanced conductors on the 33kV system• Conclusions - The Way Forward

Basics of Ampacity & SagBasics of Ampacity & SagBasics of Ampacity & SagBasics of Ampacity & Sag

Supergen - AMPerES

Ampacity = The amount of current a conductor can carry without exceeding a specified temperature

i R

heat

Increase in conductor

temperature

IMAX is defined by the max conductor temperature or the max conductor elongation

set by the operator

i R

heat

Increase in conductor

temperature

Sag

Conductor initial length

Elastic elongation

Plastic elongation

Sag at max mechanical

loading

Sag


Elastic elongation

Plastic elongation

Sag at max electrical loading Minimum clearance

to ground

Sag after re-tensioning the conductor

Sag at max electrical loading Minimum clearance

to ground

Increase tension

Sag after re-tensioning the conductor

Minimum clearance to ground

Sag at max electrical loading


Elastic elongation

Plastic elongation

Thermal elongation

Supergen - AMPerES

Basics of Ampacity & SagBasics of Ampacity & SagBasics of Ampacity & SagBasics of Ampacity & Sag

SPANMCTTension

SPAN

Sag

Supergen - AMPerES

Electrical computation

Ageing computation

OHLData

Operational Data

Newton-Raphson iteration of Change of State Equation

Conductor Tension & Sag

At TOPERATING (oC)

Conductor Ampacity

Conductor RAC at TOPERATING & ƒ SYSTEM

Weather Data

Conductor Data

Conductor Creep (IEEE Std)

(Creep-Strain Curves)

Final System Conditions

Mechanical computationIEEE 738 Std

(Current-Temperature Calculation)

Conductor Tension & Sag with Creep

At specified Load

Maximum conductor tension (MCT)

Computational MethodologyComputational MethodologyComputational MethodologyComputational Methodology

YES

Initial condition:EDT at specified

Temperature

Final condition: specified by load case

VLMWT at the specified load case

AMWT=ACWT

ACWT= RBS

SF

AMWT=IMWT

IMWT=RBS

SF

ACWT ≥ IMWTNO

Change of State equation iteration using

Newton-Raphson

VLMWT ≥ AMWT

MCT = AMWTMCT = VLMWT

AMWT

Load case (1 - 6)

At specified Load Case (1-6)

YES

NO

ConductorInsulator or fitting

Load case (1 - 6)

Load case (1 - 6)

MCT

VIBRATION LIMIT CONDUCTOR LIMIT

STRUCTURE LIMIT

Supergen - AMPerES


Ageing computation

OHLData

Operational Data



At TOPERATING (oC)

Conductor Ampacity


Weather Data

Conductor Data


(Strain-Strain Curves)





At specified Load


Mechanical ComputationsMechanical ComputationsMechanical ComputationsMechanical Computations

EXAMPLE OF LOAD CASEWIND: 380N/m2

ICE: 9.5mm & 913kg/m3

• BS EN 50423• BS EN 50341• BS EN 50182

Insulator Maximum Working Tension Absolute Conductor Working Tension

Absolute Maximum Working Tension

Vibration Limited Maximum Working

Tension

Supergen - AMPerES


Ageing computation

OHLData

Operational Data



At TOPERATING (oC)

Conductor Ampacity


Weather Data

Conductor Data







At specified Load


Electrical ComputationsElectrical ComputationsElectrical ComputationsElectrical Computations


Ageing computation

OHLData

Operational Data



At TOPERATING (oC)

Conductor Ampacity


Weather Data

Conductor Data







At specified Load



Ageing computation

OHLData

Operational Data



At TOPERATING (oC)

Conductor Ampacity


Weather Data

Conductor Data







At specified Load


RDC = (RST||RAL) at TOPoC

Skin factor

Magnetisation factor

Odd layer conductorYES

NO

RAC at TOPoC

Calculation of Ampacity (IEEE Std 738)

ICALCULATED≈IESTIMATED

NO

Electrical + physical properties of Steel core

Electrical + physical properties of

Aluminium tube

RDC at 200C

Spiralling factorSpiralling factor

RDC at TOPoC RDC at TOP

oC

Steel Aluminium

RDC at 200C

RAC + Ampacity at TOPoC

YES

BS method

Neglects steel core

in the table F.42

of standards

RDC = RAL

ASTM method

considers steel

core

RDC = RST || RAL

• BS EN 50182• ASTM B232

Supergen - AMPerES


Ageing computation

OHLData

Operational Data



At TOPERATING (oC)

Conductor Ampacity


Weather Data

Conductor Data







At specified Load


Ageing ComputationsAgeing ComputationsAgeing ComputationsAgeing Computations


Ageing computation

OHLData

Operational Data



At TOPERATING (oC)

Conductor Ampacity


Weather Data

Conductor Data







At specified Load


Predictor Equations IEEE 1283

75%RBS

20%RBS 10-year creep

line

Final after high load creep line

(75%RBS)Initial creep line

10-year plastic elongation at 20%RBS

Final conductor modulus of elasticity

strand settlement & deformation

Stress

% elongation

A

C’

D

C

C’

0

(a)

(b)

Δ Δt

Creep-Strain curve

ΔTension

Supergen - AMPerES

33kV Wood Pole Structure Analysis33kV Wood Pole Structure Analysis33kV Wood Pole Structure Analysis33kV Wood Pole Structure Analysis

1.8

m1

0.0

5m

110m

0.45mSMAX

Minimum clearance

1.8

m1

0.0

5m

1.2m 1.2m

0.45m

ENA TS 43-40ENA TS 43-90 BS 3288

BS 1990-1BS EN 62219BS EN 50423

=5.2m

=5.7m

Supergen - AMPerES

Different Conductor TechnologiesDifferent Conductor TechnologiesDifferent Conductor TechnologiesDifferent Conductor Technologies

Aluminium alloy equivalent properties to 1350-H19

Pure aluminium in between

O’ temper Aluminum

Alumina Fibers

E-glass Fibers

Carbon Fibers

ACCR (3M) ACCC/TW (CTC)

AAAC SOFT ACSR HARD ACSR

Conductor diameter (mm)0

100

200

300

400

500

600

700

800

Am

pa

cit

y (

A)

0

100

200

300

400

500

600

700

800

14PTPPPpppZones of sag for AAAC

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0 5 10 15 20 25 30Conductor diameter (mm)

Sag

(m

)

MCT (-5.6˚C)Tmax (70˚C)

Supergen - AMPerES

AAAC Performance AAAC Performance AAAC Performance AAAC Performance

Minimum point

Sag is driven by conductor self

damping vibration limit

Sag is driven by OHL structure strength

Sag is driven by conductor strength

WEAK CONDUCTOR

ZONE

EVERY DAY TENSION ZONE

WEAK OHL ZONE

At Max Electrical + Mechanical Loading

Conductor Sag

Conductor Resultant Weight

OHL strength

1

Conductor strength

1

Conductor sag

Minimum point

Conductor Diameter

Supergen - AMPerES

Analysis of AAACAnalysis of AAACAnalysis of AAACAnalysis of AAAC

14pppt

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 5 10 15 20 25 30Conductor Diameter (mm)

Sa

g (

m)

Supergen - AMPerES

AAAC Performance at different TAAAC Performance at different TMAXMAX AAAC Performance at different TAAAC Performance at different TMAXMAX

WEAK CONDUCTOR ZONE

EVERY DAY TENSION ZONE

WEAK OHL ZONE

90ºC

80ºC

70ºC

60ºC

50ºC

40ºC

-5.6ºC

At different Max Operating Temperatures

Supergen - AMPerES

SAG plots for Copper, AAAC, and ACSR conductors

0

100

200

300

400

500

600

700

800

900

1000

5 10 15 20 25 30Conductor Diameter (mm)

Am

pac

ity

(A)

90ºC

80ºC

70ºC

60ºC

50ºC

40ºC

AAAC Performance AAAC Performance AAAC Performance AAAC Performance

Supergen - AMPerES

Comparison of AAAC & ACSRComparison of AAAC & ACSRComparison of AAAC & ACSRComparison of AAAC & ACSR

Conductor Diameter

Conductor Sag

Minimum point shift

Increase in strength of

material effect

Increase of Total

conductor weight effect

Aluminium conductorSteel conductor


0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5 10 15 20 25 30Conductor diameter (mm)

Sag

(m

)

Supergen - AMPerES

Comparison of AAAC & ACSR Comparison of AAAC & ACSR Comparison of AAAC & ACSR Comparison of AAAC & ACSR

Minimum point

Minim

um point

Minimum point

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5


Sag

(m

)

Supergen - AMPerES

Comparison of AAAC & ACSR Comparison of AAAC & ACSR Comparison of AAAC & ACSR Comparison of AAAC & ACSR Creep is included in the calculations

At 70oCAt -5.6oCAAAC

hard ACSR soft ACSR

Supergen - AMPerES

pp 14pt

0

100

200

300

400

500

600

700

800


Am

pac

ity

at 7

0°C

(A

)

0

0.1

0.2

0.3

0.4

0.5

0.6

I²R

Lo

sses

(%

of

rate

d p

ow

er)

70°C

Comparison of AAAC & ACSR Comparison of AAAC & ACSR Comparison of AAAC & ACSR Comparison of AAAC & ACSR

At 70oCAt -5.6oCAAAC

hard ACSR soft ACSR

Including 10 Year CreepSAG plots for Copper, AAAC, and ACSR conductors

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

15 20 25 30Conductor diameter (mm)

Sag

(m

)


0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0


Sag

(m

)

Supergen - AMPerES

Advanced Composite Conductors Advanced Composite Conductors Advanced Composite Conductors Advanced Composite Conductors Creep is not considered

AAAC

ACCC/TWACCR

At 70oCAt -5.6oC

3MCTC

pp 14pt

0

100

200

300

400

500

600

700

800


Am

pac

ity

at 7

0°C

(A

)

0

0.1

0.2

0.3

0.4

0.5

0.6

I²R

Lo

sses

(%

of

rate

d p

ow

er)

70°C

Supergen - AMPerES

Advanced Composite Conductors Advanced Composite Conductors Advanced Composite Conductors Advanced Composite Conductors

AAAC

ACCC/TWACCR

I2R LossesAmpacity

3MCTC

Supergen - AMPerES

ConclusionsConclusionsConclusionsConclusions

• The methodology can be applied in any type & size of conductor including system design limitations & weather.

• AAAC are more suitable than the ACSR for the 33kV typical wood pole system.

• ACCC/TW develop less sag allowing uprating of the structure to 66kV.

Supergen - AMPerES

What is NextWhat is NextWhat is NextWhat is Next

Performance Analysis of a real system

Any real system?

identifying opportunities to improve the efficiency of power transmission through existing overhead...

Documents