Understanding the Mega Rule: Interference Mitigation

This is the second article in our series designed to provide clarity amid the many new complexities surrounding the Mega Rule (read the first in the series). Corrosion control and repair criteria are central to Part 3 of the Mega Rule and here we focus on challenges around interference mitigation. Throughout this series, we also present solutions designed to help informed decision making and compliance.

The Mega Rule

To recap, the Mega Rule builds on and updates existing legislation designed to reinforce a risk management approach to the safety of natural gas transmission pipelines, natural gas distribution pipelines, and hazardous liquid transmission pipelines. Its third and final part became effective in February of 2023 with a compliance deadline of February 2024. It clarifies integrity management regulations from corrosion control requirements and repair criteria to post extreme weather inspection and applies to onshore gas pipeline infrastructure spanning HCA, and non-HCA.

The Mega Rule updates are challenging but Dairyland’s expertise and technologies are proven to mitigate interference, helping to deliver compliance, ensure safety and create competitive edge.

Background

For a range of logistical, land access and environmental purposes, it is a global norm for pipelines to share Right-of-Way (ROW) with high-voltage power lines creating a network of utility corridors.  In these multi-purpose routes that often span long distances, AC corrosion risk is increased due to undesirable AC interference while also raising shock hazard risk to personnel who come in contact with the pipeline or appurtenances.

 

Challenge #2: Interference Mitigation

To understand the extent of corrosion and pipeline integrity, interference surveys are essential. Pipeline infrastructure and associated equipment have voltage limits and mitigative measures are required to reduce corrosion risk, lessen the risk to personnel, prevent costly damage and downtime.

To ensure compliance with the new regulations, interference surveys are undertaken when periodic monitoring indicates an increase in stray current, or new stray current sources are introduced. Sources of stray current can include co-located pipelines, structures, or high voltage alternating current (HVAC) or DC power lines (including from additional generation), a voltage up-rating, additional lines, new or enlarged power substations, new pipelines, or other structures. If the interference current is greater than or equal to 100 amps per meter squared a remedial action plan must be developed and implemented within a rule-stipulated time frame.

The risk of interference is heightened through the transferal of electrical energy onto a pipeline in multiple ways. Apart from the expected interference on multi-purpose routes, faults beyond the control of the pipeline operator, including lightning strikes, can take their toll on asset integrity. Furthermore, damage to overhead transmission systems from extreme weather or technical failures can increase the risk of line-to-ground damage. All these risks, and many more besides, must be mitigated against.

Solution #2: Interference Mitigation

Engineered interference mitigation systems can reduce AC voltages to an acceptable level, significantly reducing cost implications and improving safety over the operational lifespan of pipeline infrastructure. Dairyland products are proven, critical components of successful AC interference mitigation systems globally. Our decouplers such as the SSD, PCR, and PCRX, provide an effective grounding path that mitigates induced AC, while simultaneously maintaining DC isolation. Indeed, effectively utilizing decouplers in AC mitigation applications will help to minimize voltage differences to safe levels for both personnel and equipment when grounding is required to address safety and equipment concerns and isolation is required to maintain an effective cathodic protection (CP) system. Dairyland decouplers are appropriately rated to manage over-voltage conditions while simultaneously providing CP system isolation, protecting the integrity of your CP, maintaining a low impedance path to earth for AC and lightning, protecting your personnel and equipment.

With the Mega Rule impacting approximately 300,000 miles of existing onshore natural gas pipeline, and almost 20,000 miles of planned pipeline in the US, extending the life of these assets and building them in compliance with the regulations will require innovative technology and solutions.

 

Dairyland is here to help you make decisions on how our solutions can be applied to achieve Mega Rule compliance. We pride ourselves on being a reliable resource for complete technical guidance and our technical support staff is ready to support you in a variety of ways – even if you don’t end up needing our products.