SHORT CIRCUIT PERFORMANCE TEST ON 1020 kcmil ACCC/TW CONDUCTOR FOR COMPOSITE TECHNOLOGY CORPORATION

Size: px

Start display at page:

Download "SHORT CIRCUIT PERFORMANCE TEST ON 1020 kcmil ACCC/TW CONDUCTOR FOR COMPOSITE TECHNOLOGY CORPORATION"

Joleen Fletcher
5 years ago
Views:

1 To: Mr. Dave Bryant Composite Technology Corporation 2026 McGaw Avenue Irvine, CA USA SHORT CIRCUIT PERFORMANCE TEST ON 1020 kcmil ACCC/TW CONDUCTOR FOR COMPOSITE TECHNOLOGY CORPORATION Kinectrics North America Inc. Report No.: June 29, 2005 C.J. Pon Transmission and Distribution Technologies Business 1.0 INTRODUCTION A Short Circuit Test was performed on a 1020 kcmil, Aluminum Conductor, Composite Core Trapezoidal Wires (ACCC/TW) conductor for Composite Technology Corporation (CTC). The conductor consists of a single composite fiberglass/carbon fiber core covered by 2 layers of 22 annealed, trapezoidally-shaped aluminum alloy wires. The core is manufactured by CTC and the conductor is stranded by General Cable. The test was performed under CTC Purchase Order PO00668 on March 29, 2005 by Kinectrics North America Inc. personnel at 800 Kipling Avenue, Toronto, Ontario, M8Z 6C4, Canada. TEST OBJECTIVE The objective of the Short Circuit Test was to observe the thermal and mechanical performance of the 1020 kcmil ACCC/TW conductor and the 795 kcmil ACSR conductor when subjected to increasing levels of short circuit energy. Possible damages to conductors due to short circuit currents are annealing and birdcaging of the aluminum strands. It was not the intent to make direct comparisons between the ACCC/TW and ACSR conductors mainly because of the differences in the construction of the aluminum wires and the current carrying cross-section. PRIVATE INFORMATION Contents of this report shall not be disclosed without authority of the client. Kinectrics North America Inc., 800 Kipling Avenue, Toronto, Ontario M8Z 6C4

2 TEST CONDUCTORS The 1020 kcmil ACCC/TW conductor has a circular area of 1020 kcmils and has 22 trapezoidally-shaped fully annealed aluminum wires stranded in two(2) layers over one(1) round fiberglass/carbon fibre composite core rod. The outside diameter of the conductor is inches (28.14 mm) and the conductor has a rated tensile strength of 41,000 lbf (32,210 kgf). The data sheet on the 1020 kcmil ACCC/TW conductor is shown in Appendix B. The 795 kcmil ACSR has a circular area of 795 kcmils and has 26 round aluminum alloy wires stranded in two(2) layers over seven(7) round galvanized steel wires. The outside diameter of the conductor is inches (28.14 mm) and the conductor has a rated tensile strength of 31,500 lbf (14,288 kgf). TEST SET-UP The Short Circuit Test was carried out at Kinectrics Indoor High Current Facility. Test Apparatus The ACCC/TW and ACSR conductor samples, shown in Figures 1a and 1b, were tensioned horizontally about 1.5 m above the ground. The ACCC/TW conductor was terminated at both ends using FCI/Burndy compression deadend clamps. These clamps are specially designed for CTC s Composite Conductor. The catalog number is YTW451REACCC. The ACSR conductor was terminated using preformed deadend clamps. The length of each test conductor was about 10 m. The conductors were electrically connected at one end by a jumper cable such that the conductors would be subjected to the same short circuit currents. The high level short circuit currents were provided by a high level current transformer. A separate low level transformer was also connected to the test span. It provided a low level current to maintain the conductor temperature at the desired starting temperature between short circuit applications. The electrical diagram for the test is shown in Figure 2. The cables of the bus from the current transformer were connected to the conductors using grounding clamps to complete the circuit. A turnbuckle was used to tension the conductors and a dynamometer was used to measure the tension. Instrumentation and Data Acquisition The temperature in the conductors was measured at two(2) locations using fast responding thermocouples. They were spaced approximately one (1) m apart and were positioned in the conductor as follows: Thermocouple #1 (for both conductors) - between two(2) Outer Layer Aluminum Alloy Wires Thermocouple #2 (for ACCC/TW) - inserted in a small hole in the Core Thermocouple #2 (for ACSR) - between 2 galvanized steel wires The thermocouples were optically isolated from other instrumentation to prevent electrical interference into the data acquisition system. 2

3 For each short circuit application, or shot, a high-speed data acquisition system recorded the short circuit current at 5000 samples/second. The thermocouple readings from the temperature sample were recorded at 500 samples/second. TEST PROGRAM The conductors were subjected to a total of six (6) short circuit applications or shots. The low level current transformer provided sufficient current to increase the initial temperature in the outer aluminum layer in the ACCC/TW and ACSR conductors to the desired level before each shot. The tension of the conductors at these initial temperatures was approximately 15% of the RTS of the conductors. This corresponded to 6,100 lbf (2,767 kgf) for the ACCC/TW conductor and 4,725 lbf (2,143 kgf) for the ACSR conductor. The conductors were subjected to increasing levels of short circuit energy, as expressed by ka 2 -sec, until physical damage, such as birdcaging or melting of the conductor or clamps, was observed. The maximum temperatures in each conductor were recorded after each shot. If necessary, the tension in the conductor was readjusted to approximately 15% RTS before each shot. The short circuit current and duration of each shot were adjusted to produce the desired energy imparted to the conductor. Each short circuit fault was applied with the maximum possible asymmetry (ie, maximum DC Offset). The conductors were visually inspected after each shot for birdcaging, melting or other damage. The temperature of the conductor was allowed to cool by natural convection to the initial temperature before proceeding with the shot. TEST RESULTS Six(6) shots were applied to the conductors corresponding to Test No to Test No The energy levels for the shots were 542 ka 2 sec, 786 ka 2 sec, 1023 ka 2 sec, 1268 ka 2 sec, 1525 ka 2 sec and 1520 ka 2 sec. These levels were arbitrarily selected. The short circuit currents ranged from 38.1 ka rms to 38.4 ka rms. The duration of the shots ranged from 349 milliseconds to 1018 milliseconds. The data for the shots are summarized in Table 1. The data sheet for shot is missing. The temperature in aluminum wires and core vs. short circuit energy for the conductors are plotted on the graphs in Figures 3 and 4. The data sheets for each shot are shown in Appendix A. These sheets show the short circuit waveform and the temperatures of the outer aluminum wires and core for the ACCC/TW and ACSR conductors. The actual initial temperature of the outer aluminum wires on the ACCC/TW conductor before each shot ranged from 89 C to 121 C. The average initial temperature for the six(6) shots was 107 C. The actual initial temperature of the outer aluminum wires on the ACSR conductor before each shot ranged from 147 C to 171 C. The average initial temperature for the six(6) shots was 157 C. Although the same low level current was circulating through each conductor, the initial conductor of the ACCC/TW conductor was lower than the ACSR conductor because it has greater aluminum cross-section. For the ACCC/TW conductor, the maximum temperature rise in the aluminum wires above the average initial temperature ranged from 27 C for the 542 ka 2 sec shot to 97 C for the

4 ka 2 sec shot. The corresponding maximum temperatures were 134 C for the 542 ka 2 sec shot and 204 C for the 1525 ka 2 sec shot. The maximum temperature rise in the core above the average initial temperature ranged from 1 C for the 542 ka 2 sec shot to 27 C for the 1525 ka 2 sec shot. The corresponding maximum temperatures were 52 C for the 542 ka 2 sec shot and 78 C for the 1525 ka 2 sec shot. The temperature of the core when the aluminum temperature was maximum ranged from 51 C for the 542 ka 2 sec shot to 55 C for the 1525 ka 2 sec shot. For the ACSR conductor, the maximum temperature rise in the aluminum wires above the average initial temperature ranged from 35 C for the 542 ka 2 sec shot to 158 C for the 1520 ka 2 sec shot. The corresponding maximum temperatures were 192 C for the 542 ka 2 sec shot and 315 C for the 1520 ka 2 sec shot. The maximum temperature rise in the core above the average initial temperature ranged from 11 C for the 542 ka 2 sec shot to 28 C for the 1520 ka 2 sec shot. The corresponding maximum temperatures were 174 C for the 542 ka 2 sec shot and 235 C for the 1520 ka 2 sec shot. The temperature of the core when the aluminum temperature was maximum ranged from 159 C for the 542 ka 2 sec shot to 176 C for the 1520 ka 2 sec shot. KEY OBSERVATIONS ON 1020 ACCC/TW CONDUCTOR 1) The maximum temperature of the core of the 1020 kcmil ACCC/TW conductor measured during the test was 78 C. This occurred at a short circuit level of 1525 ka 2 sec with an initial outer aluminum wire temperature of 107 C. 2) The maximum temperature of the outer aluminum wires of the 1020 kcmil ACCC/TW conductor measured during the test was 204 C. This occurred at a short circuit level of 1525 ka 2 sec with an initial outer aluminum wire temperature of 107 C. 3) The outer surface of the core was visually examined after the short circuit test. There were no signs of damage or degradation to the outside surface of the core. 4) The onset of birdcaging of the aluminum wires was evident after the first shot (542 ka 2 sec). Figures 5 and 6 show birdcaging of the ACCC/TW conductors after shots and (1520 ka 2 sec).. KEY OBSERVATIONS ON 795 ACSR CONDUCTOR 1) The maximum temperature of the core of the 795 kcmil ACSR conductor measured during the test was 235 C. This occurred at a short circuit level of 1520 ka 2 sec with an initial outer aluminum wire temperature of 157 C. 2) The maximum temperature of the outer aluminum wires of the 795 kcmil ACSR conductor measured during the test was 315 C. This occurred at a short circuit level of 1520 ka 2 sec with an initial outer aluminum wire temperature of 157 C. 3) The galvanized steel core wires were visually examined after the short circuit test. There was no signs of any damage or degradation to the steel wires. 4

5 4) The aluminum wires stated to loosen during the third shot (1023 ka 2 sec). Figure 7 shows birdcaging of the ACSR conductor after shot (1520 ka 2 sec). ACKNOWLEDGEMENTS Messrs. C. Maurice and M. Goodnough performed the Short Circuit Test. Prepared by: C.J. Pon Principal Engineer Transmission and Distribution Technologies Business Approved by: CJP:JC Dr. J. Kuffel General Manager Transmission and Distribution Technologies Business DISCLAIMER Kinectrics North America Inc. has prepared this report in accordance with, and subject to, the terms and conditions of the contract between Kinectrics North America Inc. and CTC Inc., dated June 3, Kinectrics North America Inc.,

6 Table 1 Short Circuit Test Results on 1020 kcmil ACCC/TW and 795 kcmil ACSR Conductors Test Date March 29, 2005 Test # Short Circuit Current Duration Energy Initial Temp Avg. Init. Temp Temp. Rise Initial Temp. Avg. Init. Temp. Temp. Rise Maximum Temp. Above Avg. Initial Temp. Core Temp. at Max. Al Temp Observations RMS (ka) Peak (ka) (msec) (ka²s) of Al ( C) of Al ( C) of Al ( C) of Core ( C) of Core ( C) of Core ( C) of Al ( C) of Core ( C) ( C) T#1 T#1 T#1 T#2 T#2 T#2 T#1 T# kcmil ACCC/TW Conductor Onset of birdcaging of outer Alum. wires Similar to Al wires very loose even after cooling Large permanent birdcage, 1.5 m from DE Similar to Similar to kcmil ACSR Conductor No birdcaging No birdcaging Al wires loosening Al wire deforming at DE Significant damage Significant damage Thermocouple #1 - Between two(2) Outer Layer Aluminum Alloy Wires Thermocouple #2 Inside Composite Core for ACCC/TW - Between 2 galvanized steel wires for ACSR Values in red are plotted on the graphs in Figures 3 and 4

Test Figure 1b Deadend Clamp Configuration for 1020 kcmil

7 Figure 1a 1020 kcmil ACCC/TW Conductor (foreground) and 795 kcmil ACSR Conductor (background) Installed for Short Circuit Test Figure 1b Deadend Clamp Configuration for 1020 kcmil ACCC/TW Conductor (background) and 795 kcmil ACSR Conductor (foreground) 7

8 Tower Conductor Under Test Tower Dynamometer Turnbuckle Deadend Hardware Thermocouples Deadend Hardware High Current Circuit Insulator Insulator Isolation Switch Isolation Switch 25 Volts Current Limiting Impedance Make Switch 0-240Volt Pre-Heating Circuit Supply Transformer Figure 2 Electrical Circuit for Short Circuit Test 8

9 Temperature ( C) ACCC AL strands ACCC Core ACCC AL max Linear (ACCC AL strands) Linear (ACCC Core) Linear (ACCC AL max) Short Circuit Energy (ka²sec) Figure 3 Temperature in Outer Aluminum Wires and Core vs. Short Circuit Energy for 1020 kcmil ACCC/TW Conductor Temperature ( C) Short Circuit Energy (ka²sec) ACSR AL strands ACSR Core ACSR AL max Linear (ACSR AL strands) Linear (ACSR Core) Linear (ACSR AL max) Figure 4 Temperature in Outer Aluminum Wires and Core vs. Short Circuit Energy for 795 kcmil ACSR Conductor 9

10 Figure 5 Onset of Birdcaging on 1020 kcmil ACCC/TW Conductor During Shot (542 ka 2 sec) Figure 6 Birdcaging of 1020 kcmil ACCC/TW Conductor after Shot (1525 ka 2 sec) 10

11 Figure 7 Birdcaging of 795 ACSR Drake Conductor after Shot (1525 ka 2 sec) 11

12 APPENDIX A Short Circuit Test Data Sheets for 1020 kcmil ACCC/TW and 795 kcmil ACSR Conductors - Test Date March 29, 2005 A-1

13 A-2

14 A-3

15 A-4

16 A-5

17 A-6

18 APPENDIX B Specifications for 1020 kcmil ACCC/TW Conductor B-1

19 B-2

20 B-3

21 DISTRIBUTION Mr. D. C. Bryant(2) Mr. C. Pon Composite Technology Corporation 2026 McGaw Avenue Irvine, CA USA Transmission and Distribution KB104

Kinectrics North America Inc. Report No.: K RC-0001-R01 November 4, 2005

To: Colin McCullough Specialty Materials Division Composite Conductor Program 3M Company 3130 Lexington Ave. South Eagan, MN, 55121 USA KINECTRICS NORTH AMERICA INC. TEST REPORT FOR 3M TO COMPARE THE SALT