The objective of this overall project is to provide an assessment tool for determination of safe separation distance between high voltage power line tower/pole footings and underground pipelines. This tool is to address arcing distance while also considering the following issues:
- Corrosion of tower footings and grounding conductors.
- Puncture of pipeline coatings due to faults.
- Flashover damage to pipeline isolation flanges.
- Possible hazardous step and touch potentials to pipeline and utility workers.
Stage 1 of this work (3715A) is nearing completion; its findings are now being implemented into the scope of Stage 2 work. Stage 2 of this work will complete investigation and testing to determine pipeline to electric supply line separation needed to prevent sustained 60 Hz arcing. Stage 2 tests will determine:
- Impulse soil breakdown Ei (kV/m)
- Power frequency soil breakdown Ep (kV/m)
- Power frequency arc sustainability Es (kV/m), following impulse breakdown by lightning and insulator flashback
The group has decided to break down these Stage 2 activities into two steps – the first (Stage 2A) in order to validate the arc model and laboratory test setup with a pilot demonstration, prior to full-scale testing done in the next step (Stage 2B). This allows the project sponsors a “checkpoint” with which we could opt for a different contractor and/or a revision in project scope, if results obtained in pilot testing (Stage 2A) fail to provide initial validation of the arc model and test setup at the heart of this work.