1. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 EVALUATION OF HIGH-TEMPERATURE FLUORINATED ETHERS (PFPE) FOR POWER CONNECTORS OPERATING AT EXTREME SERVICE CONDITIONS Barry JOHNSON and Dmitry LADIN Tyco Electronics – Canada bjohnson@tycoelectronics.com Milenko BRAUNOVIC MB Interface - Canada, mbinterface@yahoo.com bjohnson@tycoelectronics.com mbinterface@yahoo.com

2. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Competitive Industry From system growth to prolonging the operating life Increased energy consumption in densely populated areas Transmission/Distribution lines carry greater loads Operating temperature of conductors raised beyond 130 0 C New type of high temperature conductor (ACSS) Stability of power connections at extreme operating conditions

3. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Lubrication of Power Connections Contact aid compounds commonly used for Al and Cu Contact zone protection Low thermal stability of currently used compounds Inertness and low viscosity of fluorinated ethers PFPE-based lubricants can sustain operating temperatures as high as 200 0 C

4. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Lubricants Selection Maximum operating temperature range Formulation: base oil and additives Thickeners: –not melting –improved adhesion to the substrate –lower wear rates

5. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 UV Resistance Per ASTM G-53-95 and ASTM D-638-95 Accelerated Weathering Tester: cycles of 4 hrs UVB at 60 0 C, followed by 4 hrs of condensation at 50 0 C Lubricant failed: no longer can be spread and/or has severe cracking

6. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 WEATHERING TESTER

7. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Long-Term Temperature Exposure Forced Air Oven set to 200 0 C Exposure time: more than 2000 hrs Material Examination: –Discoloration –Cracking –Hardening

8. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Appearance of the Lubricants (Thermal Ageing) BEFORE EXPOSURE AFTER EXPOSURE PASSED FAILED

9. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Thermogravimetric Analysis (TGA) Determination of thermal stability Weight change measurement Heating rate: 10 0 C/min N3 is stable up to 400 0 C

10. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Current Cycling Tests Test I: measured contact resistance and temperature of lubricated Al-to-Al busbar bolted joints: –Thin layer of the lubricant spread over overlapping zones –Joints repeatedly heated up to 200 0 C (for 5 min) and cooled to ambient temperature

11. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Current Cycling Tests Test II: wedge connectors assembled with 336.4 kcmil ACSS conductors: –Followed modified ANSI 119.4 Class AA procedure –Temperature of the control conductor was raised to 200 0 C

12. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Results of the Current Cycling Tests Typical data sample: lubricated Al to Al wedge connectors N3 and C1 lubricants are the base formulation for effective high temperature applications µ µ

13. JOHNSON_CA_author_ALPHA1_BLOCK1 Barcelona 12-15 May 2003 Discussion & Conclusions Two PFPE lubricants with sufficient UV and thermal ageing stability are identified The lubricants were effectively utilized as contact-aid compounds in current cycling tests Results obtained under controlled laboratory conditions Suggested materials should be subjected to the field service conditions Necessary fillers and metallic additions are to be incorporated to make HT contact-aid compounds