AC Corrosion Mitigation
The professionals at Point Integrity Solutions understand the importance of using mitigation systems to improve safety and/or control corrosion. We can help your induced AC issues on existing and proposed pipelines. Our extensive industry experience mitigating this complex issue has transformed the solution to a straightforward approach with successful results.
Alternating Current (AC) Interference is
- Proportional to length of parallelism between pipeline and power line
- Proportional to power line current
- Inversely proportional to separation distance of power line and pipeline
At Point Integrity Solutions we understand that induced AC interference is of concern for two very important reasons:
- Personnel Safety
- Step and Touch Potentials at 15 volts AC and above
- Conductive coupling from AC fault currents and lightning strikes
- Accelerated Corrosion
- Can be very severe at current densities above 20 Amps/m2
Personnel Safety is a concern for not only people working on the pipeline, but for the general population located in close proximity to the interference.
Points of potential dangerous situations include:
- Above ground piping
- Appurtenances such as valve operators, block valve bypass piping, pigging facilities, CP test stations and casing vent pipes
- Below ground piping where a cut during construction activities causes a "hot spot" for AC voltage accumulation
OSHA Standard 2207 part 1926 and NACE RP-0177-2000 both discuss keeping AC open circuit potentials below 15 volts AC rms to minimize potential dangers of excessive current flow through the human body.
Accelerated corrosion of over 50 mills per year has been observed on pipelines co-located within high voltage AC power line corridors.
Above Ground Indicators of Potential AC Interference
- ROW is parallel or crosses at shallow angle to high tension AC power lines
- Swampy/moist areas
- Pipeline and power lines have a change in geometry, such as point of convergence, divergence, or they cross each other
Below Ground Indicators of Potential AC Interference
- Medium to low resistivity soil conditions
- Good to excellent pipeline coatings
- Effective insulating flanges
Point Integrity has extensive expertise in the mitigation of AC interference, and would be happy to provide more information regarding specific solutions for your company.