3-comparisonofcreeptest

Craig Pon Kinectrics, Inc

& Otto J. Lynch, P.E.

Power Line Systems, Inc.

Creep Test Study - A Comparison of Test Durations

July 25, 2012 Conductors and Accessories WG

San Diego, CA

Outline

1. Motivation 2. Objective of the Study 3. Study Process 4. Typical Creep Test Result for 1000 hours 5. Comparison of 10 year extrapolation using 1000 hour and 500 hour data

Why is the Creep Test 1000 hours in duration? Is it necessary to be that long?

Motivation

To determine the difference of using 500 hour data instead of 1000 hour data on the linear extrapolation to 10 years

To determine the effect of this difference on Sag-Tension calculations

Objective of the Study

Total 67 conductors/cables analyzed (performed in accordance with AA or IEC 61395)

• Category 1 – 25 Conductors (ACSR, AACSR, ACSR/AW, ACSR/TW) • Category 2 – 34 OPGW Cables (Various designs) • Category 3 – 8 other Conductors (AAAC, ACAR, ADSS, HTLS)

Linear regressions (y = AxB ) performed on 1000 hour and 500 hour data from the same test

Regressions extrapolation to 10 years (87,600 hours) Comparison of 10 year creep

Study Process

1000 Hour Regression y = 5E-05x0.2091

R² = 0.9962

500 Hour Regression y = 5E-05x0.2137

R² = 0.9968

0.00001

0.00010

0.00100

0.01000

1 10 100 1000 10000 100000

Stra

in (m

m/m

m)

Time (hrs)

ACSR/TW "Erie", 24.13 mm, 16/7

1000 Hour

500 Hour

Power (1000 Hour)

Power (500 Hour)

Typical Creep Test Result for 1000 hours

Category 1 – 25 Conductors (ACSR, etc)

Cable Type Code Name Cable Diameter (mm) Stranding Linear Mass

(kg/km)R2 value

1,000 hours

R2 value1,000 hours

10 year strainusing 1,000 hour data

10 year strain using 500hour data

Absolute Strain Difference

% Strain Difference

A (y-intercept) B (slope) A (y-intercept) B (slope)

1 AACSR WASKAG 23.53 23/7 0.0000758 0.2352600 0.0000758 0.2352600 0.998 0.997 0.0010275 0.0010275 0.0000000 0.0000%2 AACSR 33.90 60/19 2368 0.0000353 0.2359900 0.0000349 0.2411300 0.983 0.980 0.0004830 0.0005086 0.0000256 5.2988%3 ACSR BERSFORT 35.58 48/7 2375 0.0001223 0.1838700 0.0001221 0.1847800 0.999 0.999 0.0008689 0.0008775 0.0000086 0.9889%4 ACSR BLUEJAY 31.98 45/7 1867 0.0000508 0.1956300 0.0000503 0.2004300 0.975 0.970 0.0004202 0.0004419 0.0000217 5.1709%5 ACSR CANARY 29.19 54/7 0.0000892 0.1656500 0.0000896 0.1635100 0.994 0.993 0.0004986 0.0004867 -0.0000119 2.3858%6 ACSR CARDINAL 30.42 54/7 1829 0.0000594 0.1878400 0.0000593 0.1880400 0.996 0.995 0.0004441 0.0004450 0.0000010 0.2161%7 ACSR CURLEW 31.59 54/7 1978 0.0000288 0.2249200 0.0000285 0.2291500 0.978 0.972 0.0003431 0.0003581 0.0000150 4.3670%8 ACSR CURLEW 31.62 54/7 1983 0.0001988 0.1327700 0.0001986 0.1333500 1.000 1.000 0.0007021 0.0007072 0.0000051 0.7230%9 ACSR CURLEW 31.68 54/7 0.0000473 0.2050000 0.0000474 0.2039500 0.999 0.998 0.0004400 0.0004352 -0.0000048 1.0816%

10 ACSR CURLEW AW 31.68 54/7 1896 0.0000588 0.2166200 0.0000584 0.2200200 0.989 0.987 0.0006331 0.0006555 0.0000223 3.5294%11 ACSR CURLEW GS 31.68 54/7 1980 0.0000682 0.2062200 0.0000678 0.2084300 0.999 1.000 0.0006443 0.0006593 0.0000150 2.3231%12 ACSR HAWK 21.79 26/7 977 0.0000367 0.2057900 0.0000364 0.2093800 0.994 0.994 0.0003453 0.0003583 0.0000131 3.7819%13 ACSR HAWK 21.79 26/7 977 0.0000476 0.2055200 0.0000471 0.2102700 0.993 0.993 0.0004455 0.0004680 0.0000224 5.0356%14 ACSR LYNX 19.53 30/7 842 0.0000413 0.2026400 0.0000418 0.1973400 0.997 0.999 0.0003730 0.0003529 -0.0000201 5.3869%15 ACSR LYNX 19.53 30/7 842 0.0000524 0.1935400 0.0000524 0.1935700 0.998 0.998 0.0004217 0.0004218 0.0000001 0.0269%16 ACSR PHEASANT 35.11 54/19 1784 0.0000655 0.1901400 0.0000654 0.1909500 0.998 0.997 0.0005046 0.0005090 0.0000044 0.8658%17 ACSR SQUAB 24.51 26/7 1240 0.0000419 0.2063700 0.0000417 0.2090200 0.997 0.996 0.0003969 0.0004080 0.0000111 2.7856%18 ACSR SQUAB 24.53 26/7 1239 0.0000623 0.1913900 0.0000617 0.1931900 0.981 0.983 0.0004878 0.0004947 0.0000069 1.4191%19 ACSR 24.00 13/19 1621 0.0000623 0.1715100 0.0000623 0.1715100 0.999 0.998 0.0003762 0.0003762 0.0000000 0.0000%20 ACSR 33.15 54/19 2166 0.0000960 0.2196700 0.0000955 0.2219700 0.997 0.997 0.0010731 0.0010985 0.0000254 2.3682%21 ACSR/AW DOVE 23.55 26/7 1140 0.0000399 0.1913700 0.0000398 0.1932900 0.995 0.994 0.0003127 0.0003191 0.0000064 2.0552%22 ACSR/AW MERLIN 17.35 18/1 532 0.0000258 0.2209600 0.0000258 0.2210800 0.990 0.987 0.0002933 0.0002936 0.0000003 0.1021%23 ACSR/AW PENGUIN 14.31 6/1 412 0.0001359 0.1593400 0.0001363 0.1582100 0.993 0.991 0.0006974 0.0006886 -0.0000088 1.2660%24 ACSR/AW QUAIL 11.34 6/1 259 0.0000175 0.2213600 0.0000174 0.2239600 0.993 0.992 0.0001999 0.0002053 0.0000054 2.6940%25 ACSR/TW ERIE 24.13 16/7 1400 0.0000485 0.2090600 0.0000480 0.2137000 0.996 0.997 0.0004753 0.0004985 0.0000232 4.8816%

0.0000111 2.3159%-0.0000114 2.5301%

Creep Coefficientsusing 1,000 hour data

Creep Coefficientsusing 500 hour data

Average strain for overestimated 500 hour extrapolation - ACSRAverage strain for underestimated 500 hour extrapolation - ACSR

Category 2 – 34 OPGW Cables


(kg/km)R2 value

1,000 hours

R2 value1,000 hours




% Strain Difference


1 OPGW AA 21.70 30/7 961 0.0000437 0.2347400 0.0000434 0.2379800 0.997 0.996 0.0005883 0.0006075 0.0000192 3.2710%2 OPGW AA/ACS 12.10 6/1 363 0.0000481 0.1959600 0.0000481 0.1959600 0.994 0.995 0.0003991 0.0003991 0.0000000 0.0000%3 OPGW AA/ACS 12.86 8/1 437 0.0001070 0.1724700 0.0001070 0.1724300 0.998 0.998 0.0006546 0.0006542 -0.0000003 0.0529%4 OPGW AA/ACS 13.60 10/1 453 0.0000746 0.1937400 0.0000743 0.1953200 0.998 0.997 0.0006019 0.0006121 0.0000102 1.6904%5 OPGW AA/ACS 14.00 14/6 505 0.0000392 0.1930300 0.0000389 0.1960000 0.989 0.986 0.0003133 0.0003233 0.0000100 3.1811%6 OPGW AA/ACS 14.20 9/1 580 0.0000714 0.1895000 0.0000706 0.1946700 0.996 0.997 0.0005455 0.0005762 0.0000307 5.6288%7 OPGW AA/ACS 14.20 9/1 582 0.0000569 0.1678300 0.0000568 0.1691100 0.998 0.997 0.0003276 0.0003323 0.0000047 1.4455%8 OPGW AA/ACS 15.24 12/9 540 0.0000409 0.1901500 0.0000407 0.1921100 0.992 0.992 0.0003155 0.0003217 0.0000062 1.9622%9 OPGW AA/ACS 15.25 12/7 621 0.0000851 0.1396500 0.0000856 0.1368000 0.995 0.994 0.0003318 0.0003205 -0.0000113 3.3936%

10 OPGW AA/ACS 15.25 12/7 540 0.0000438 0.2064500 0.0000432 0.2125900 0.995 0.996 0.0004151 0.0004422 0.0000272 6.5407%11 OPGW AA/ACS 15.80 18/13 599 0.0000933 0.1723700 0.0000936 0.1710200 0.993 0.991 0.0005703 0.0005618 -0.0000085 1.4826%12 OPGW AA/ACS 15.80 18/13 599 0.0001328 0.1881500 0.0001342 0.1834800 0.997 0.995 0.0009973 0.0009487 -0.0000486 4.8728%13 OPGW AA/ACS 16.42 11/1 521 0.0000472 0.2137500 0.0000463 0.2230300 0.987 0.990 0.0004905 0.0005393 0.0000487 9.9371%14 OPGW AA/ACS 17.10 14/1 719 0.0000695 0.1942600 0.0000688 0.1984700 0.995 0.995 0.0005644 0.0005900 0.0000256 4.5296%15 OPGW AA/ACS 17.10 13/9 765 0.0000587 0.2176900 0.0000582 0.2214900 0.995 0.995 0.0006408 0.0006661 0.0000253 3.9411%16 OPGW AA/ACS 19.40 24/19 812 0.0000411 0.2025200 0.0000407 0.2074500 0.994 0.995 0.0003711 0.0003907 0.0000196 5.2800%17 OPGW AA/ACS 19.40 24/19 812 0.0001815 0.1596500 0.0001803 0.1626800 0.997 0.998 0.0009350 0.0009678 0.0000328 3.5060%18 OPGW AA/ACS 19.80 22/1 822 0.0000735 0.2109100 0.0000729 0.2147000 0.999 0.999 0.0007368 0.0007661 0.0000293 3.9755%19 OPGW AA/ACS 20.00 24/1 809 0.0000642 0.1781800 0.0000639 0.1800600 0.998 0.998 0.0004235 0.0004323 0.0000087 2.0657%20 OPGW AA/ACS 22.90 14/9 1270 0.0000516 0.1956800 0.0000512 0.1986200 0.997 0.997 0.0004264 0.0004398 0.0000134 3.1332%21 OPGW AA/ACS 22.90 14/9 1780 0.0000600 0.1862400 0.0000595 0.1893600 0.998 0.999 0.0004393 0.0004541 0.0000149 3.3820%22 OPGW AA/ACS 24.80 30/1 1214 0.0000767 0.1602400 0.0000766 0.1611500 0.998 0.998 0.0003986 0.0004028 0.0000042 1.0488%23 OPGW ACS 10.50 6/1 406 0.0000524 0.1792200 0.0000519 0.1832000 0.994 0.994 0.0003502 0.0003656 0.0000154 4.4031%24 OPGW ACS 11.50 10/1 460 0.0000751 0.1680900 0.0000751 0.1680900 0.996 0.996 0.0004337 0.0004337 0.0000000 0.0000%25 OPGW ACS 11.70 10/1 451 0.0000765 0.1600100 0.0000763 0.1611700 0.999 0.999 0.0003959 0.0004011 0.0000052 1.3198%26 OPGW ACS 12.00 6/1 529 0.0000565 0.1932900 0.0000559 0.1983500 0.994 0.995 0.0004532 0.0004780 0.0000248 5.4731%27 OPGW ACS 12.60 6/1 586 0.0000350 0.2139300 0.0000348 0.2165700 0.996 0.995 0.0003647 0.0003747 0.0000100 2.7470%28 OPGW ACS 12.80 14/1 518 0.0000406 0.2315000 0.0000395 0.2438400 0.981 0.986 0.0005254 0.0005941 0.0000687 13.0742%29 OPGW ACS 13.00 7/1 528 0.0000409 0.2456800 0.0000402 0.2532300 0.991 0.992 0.0006292 0.0006779 0.0000487 7.7322%30 OPGW ACS 13.46 8/1 447 0.0000641 0.2109200 0.0000638 0.2117100 0.991 0.991 0.0006425 0.0006464 0.0000039 0.6070%31 OPGW ACS 14.80 9/1 694 0.0000910 0.1611600 0.0000898 0.1670400 0.990 0.992 0.0004787 0.0005114 0.0000327 6.8322%32 OPGW ACS 16.60 10/1 720 0.0000896 0.1838900 0.0000889 0.1875200 0.996 0.996 0.0006371 0.0006624 0.0000252 3.9622%33 OPGW 12.00 6/1 532 0.0000775 0.1556000 0.0000773 0.1567000 0.998 0.998 0.0003776 0.0003824 0.0000047 1.2559%34 OPGW 16.40 38/61 598 0.0001529 0.0842973 0.0001528 0.0844025 0.998 0.997 0.0002462 0.0002465 0.0000003 0.1287%

0.0000184 3.6164%-0.0000228 3.2496%



Average strain for overestimated 500 hour extrapolation - OPGWAverage strain for underestimated 500 hour extrapolation - OPGW

Category 3 – 8 Conductors (Other)


(kg/km)R2 value

1,000 hours

R2 value1,000 hours




% Strain Difference


1 AAAC 24.64 37 WIRE 986 0.0000775 0.2190100 0.0000768 0.2231100 0.993 0.990 0.0008600 0.0008962 0.0000362 4.2100%2 AAAC 28.00 37 WIRE 0.0000637 0.1926700 0.0000629 0.1978900 0.987 0.986 0.0005069 0.0005355 0.0000287 5.6543%3 ACAR 30.38 18/19 1506 0.0000206 0.2328200 0.0000204 0.2360200 0.996 0.996 0.0002705 0.0002793 0.0000088 3.2529%4 ADSS ADSS 11.80 99 0.0001514 0.2810400 0.0001514 0.2810400 0.989 0.989 0.0035578 0.0035578 0.0000000 0.0000%5 ADSS ADSS 16.80 188 0.0004278 0.1173800 0.0004278 0.1173800 0.987 0.988 0.0011991 0.0011991 0.0000000 0.0000%6 GSTACSR 31.50 53/7 1938 0.0000073 0.2610900 0.0000073 0.2648500 0.995 0.994 0.0001357 0.0001407 0.0000051 3.7343%7 HVCRC/TW DRAKE 28.14 14/9 1555 0.0002029 0.1866800 0.0002028 0.1870200 0.999 0.999 0.0014952 0.0015006 0.0000054 0.3611%8 STACIR/AW MOOSE 31.77 54/7 0.0039840 0.0117700 0.0039730 0.0129800 0.849 0.862 0.0005710 0.0006325 0.0000614 10.7536%

0.0000182 3.4958%Average strain for underestimated 500 hour extrapolation



Average strain for overestimated 500 hour extrapolation

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

0.0040

0 10 20 30 40 50 60 70

Stra

in (m

m/m

m)

Test Number

10 Year Strain Using 1000 Hour Data

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

0.0040

0 10 20 30 40 50 60 70

Stra

in (m

m/m

m)

Test Number

10 Year Strain Using 500 Hour Data

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

0.0040

0 10 20 30 40 50 60 70

Stra

in (m

m/m

m)

Test Number

10 Year Strain Using 1000 hour and 500 hour data

500 HourExtrapolation1000 HourExtrapolation

-10% -5% 0% 5% 10% 15%

Percent Difference of 10 Year Strain Extrapolation

69% of Data (0%-5%)

500 hour extrapolation > 1000 hour extrapolation 500 hour extrapolation < 1000 hour extrapolation

Translate into Sag Tension

Compare differences of Creep Sags between; – ‘Standard’ Aluminum Association Stress-Strain Data – 1000 Hour Creep – 500 Hour Creep

Challenge: How to get from single creep point to full nonlinear creep calculations

Standard CANARY ACSR

Stress-Strain and Creep Values for Outer Aluminum

CANARY Load vs. Elongation

Computed Data Points

Data points are calculated at user-defined intervals for existing stress-strain and creep polynomials (default is 20)

Plot of Data Points on Graph

Creep Options

Revised Elongation Values

Calculate revised elongation from creep values proportional to tension.

Revised Creep Polynomials

Recalculate creep polynomials to recreate the new creep curve.

1000 Hour Graph

500 Hour Graph

Sag Results

To calculate sags after Creep, tensions were constrained to 25% RTS at Initial, 60°F as the control point (i.e. “As Strung” condition.)

For discussion, sags are presented at 0°F, 60°F, and 212°F after Creep

Typical Sag-Tension Run

Sag Differences - Canary

Strain difference between 500 and 1000 hour test is 5.17%

Sag difference between 500 and 1000 hour test is 0.05 feet; 0.6 inches!

At 212°F, there is no difference.

Temperature Sag Difference(°F) Standard Modified 1000 Hour 500 Hour 1000 Hr - 500 Hr

0 17.39 17.35 16.68 16.63 0.0560 21.54 21.52 20.84 20.79 0.05

212 30.6 30.6 30.6 30.6 0

Sag (ft)Canary 54/7 ACSR

Sag Differences - Bluejay

Strain difference between 500 and 1000 hour test is -2.39%

Sag difference between 500 and 1000 hour test again only 0.05 feet; 0.6 inches!

At 212°F, difference is less than ½”!


0 21.45 21.28 19.26 19.31 -0.0560 25.87 25.7 23.8 23.85 -0.05

212 35.57 35.43 33.93 33.89 0.04

Sag (ft)Bluejay 45/7 ACSR

Sag Differences - Hawk


There is NO sag difference between 500 and 1000 hour test.

At 212°F, difference is 0.36 inches.


0 16.23 16.14 13.87 13.87 060 20.41 20.33 17.7 17.73 -0.03

212 28.71 28.71 27.88 27.91 -0.03

Hawk 26/7 ACSRSag (ft)

Sag Differences - Pheasant


Sag difference between 500 and 1000 hour test again only 0.01 feet; negligible.

At 212°F, difference is also neglible.


0 18.66 19.05 17.23 17.24 -0.0160 22.95 23.33 21.54 21.57 -0.03

212 31.8 31.8 31.53 31.54 -0.01

Pheasant 54/19 ACSRSag (ft)

Summary

There is negligible difference in final sags after 10 year creep whether a 1000 hour or 500 hour creep test is performed.

There is more value performing 2 x 500 hour tests versus 1 x 1000 hr test

Future Work

Perform a similar analysis using 100 hour data

Validate single tension creep test with multiple tension creep tests

Questions/Discussion

Craig Pon Kinectrics, Inc

[email protected]

& Otto J. Lynch, P.E.

Power Line Systems, Inc. [email protected]

3-comparisonofcreeptest

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