Barry tested a D.E.W. Line rope with portable hot stick testers and a rope tester, comparing results to High Voltage (HV) testing.
Summary
Barry has recently performed a high number of tests using a Barry D.E.W. Line rope using two brands of portable hot stick testers and one rope tester. Results were compared to test results from High Voltage (HV) testing. Testing methods were adapted from test parameters found in the IEEE 516 Guide for Maintenance Methods on Energized Power Lines methods for testing hot sticks (horizontal set-up with 75 kV a.c. across 12 inches with no shielding of capacitive currents).
It should be noted that Barry D.E.W. Line rope tools are routinely subjected to Design and Certification testing according to I.E.C.62192 Live Working Insulating Ropes and ASTM F-1701Unused Ropes with Special Electrical Properties. The leakage values obtained during the I.E.C and ASTM HV test are lower when the capacitive currents are shielded which is more reflective of the true leakage current values of the rope.
Hypotheses
Testing was performed to test two hypotheses:
- To determine whether the portable instruments could detect water and humidity contamination present in and/or on the surface of the D.E.W. Line Insulating Rope products.
- To determine whether a correlation could be made between the HV test results vs the results from the portable hot stick testers.
Methodology
Conditioning for the testing consisted of spraying water on the surface of ropes and injecting volumes of water (2 cc and 4 cc) under the thermoplastic extruded jacket using a needle and syringe.
Electrical leakage current testing was performed at high voltage (horizontal 75 kV a.c. across 12 inches)
as well as using portable hot stick testers by A.B. Chance, Hastings, and a rope tester by Greenlee across the entire length of the sample.
Results and Conclusion:
Test results demonstrated that the Chance and the Hastings testers perform well to detect water/ humidity contamination present in the D.E.W. Line Insulating Rope products. These instruments detect the presence of both external (surface) moisture as well as internal moisture. Both hot stick testers gave comparable results.
This validated the first hypothesis.
The second hypothesis was also validated as test results show that there is a correlation between the HV test results, and the results obtained from the portable hot stick testers. As the leakage values rise during HV testing, so do the leakage values rise on the portable hot stick testers. Threshold values could be determined on the portable hot stick testers which could serve in the field to assess whether a rope was fit to be put in service. Results confirm the Pre-Use Electrical Testing methodology described in Section 6.4.2 of the User Instructions Manual for Barry D.E.W. Line Insulating Rope Equipment.
Microsoft Word - mi-dew-Note: ne-isulating-rope-equipment-en-rev6_2022-11-30 (barry.ca)
Notes:
- Further to testing of Barry D.E.W. Line Insulating Rope NF 3400, we found that the Greenlee Rope Tester should not be used on any Barry D.E.W. Line rope products rope as this instrument does not have sufficient output voltage to detect the presence of external or internal moisture.
- We tested another rope model commonly used for rescue during energized conditions (or where a risk of induction may be present) with the Greenlee Rope Tester. This rope is a Technora (aramid) fiber rope with a kernmantle braid construction which has been dry treated. The reason for testing was to see whether the Greenlee Rope Tester could detect moisture contamination on this type of rope. The results were positive, however, it demonstrated that this rope could potentially flashover with the presence of a light moisture contamination. Further investigation should be carried by users of this type of rope for applications under these conditions and on the use of this rope tester.
