After two years, the scale and scope of the Mega Rule updates continue to present challenges to pipeline operators. In this article, Dairyland Electrical Industries provides clarity amid the many complexities of the Mega Rule, while presenting solutions to some of the key challenges, to enable informed decision making and compliance.
Background
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 final part became effective in 2023 with a compliance deadline of February 2024.
Part 2 of the Mega Rule builds on its preceding parts that respectively tackle maximum allowable operating pressure (MAOP) and integrity management near high-consequence areas (HCAs), and the extension of federal safety requirements to onshore gas gathering pipelines with large diameters and high operating pressures.
It clarifies integrity management regulations from corrosion control requirements and repair criteria to post extreme weather inspection. It applies to onshore gas pipeline infrastructure spanning both HCA, and non-HCA.
Compliance with the Mega Rule in its entirety is firmly the responsibility of operating companies, the reality of which will vary depending upon the existing systems in place. Rule updates such as these can be challenging and implementing a compliant integrity management program has time and cost implications. However, Dairyland’s expertise and technologies can be put to work to ensure compliance, safety, and competitive edge.
Challenge #1: External Corrosion
To ensure compliance, pipelines must be monitored to determine cathodic protection (CP) levels. Definitively proving that a CP system is providing the degree of corrosion protection required is time-consuming and often inaccurate. Field testing has shown that interrupted surveys can sometimes be impacted by combinations of factors, such as pipeline coatings, soil resistivity, and the capacitance of traditional decouplers resulting in excessively electro-negative instant-off values. Nonetheless, where CP readings are below the required level, a close-interval-survey (CIS) is required to be completed. The CIS needs to be completed both upstream and downstream of the reading.
Any deficiencies must be remedied within a rule-stipulated window and following the completion of remedial action, an interrupted CIS must be undertaken again to ensure the pipeline potential readings are acceptable – incurring time and cost implications and increasing risk to personnel.
Solution #1: PCRX, The CIS Solution
Dairyland’s PCRX is the most sophisticated decoupler available globally. A solid-state, maintenance-free device, it is designed to simultaneously provide DC decoupling and AC continuity/grounding when used with CP structures. The PCRX provides typical decoupler functions with the additional benefit of electronically compensating for capacitance effects during interrupted surveys, including CIS. This prevents the device from contributing to errors in potential readings. The PCRX compensates to overcome capacitive effects, ensuring accurate and timely potential measurements. It does this without sacrificing the rugged over-voltage protection, AC mitigation, CP isolation, and safety grounding of Dairyland’s standard decoupling products.
In multi-purpose corridors where pipelines share the Right-of-Way (ROW) with high-voltage power lines, corrosion risk is increased, as is safety risk to personnel. PCRX, however, will provide an effective grounding path that mitigates induced AC, while simultaneously maintaining DC isolation. This is possible because PCRX provides a continuous path to ground for induced AC while blocking DC simultaneously. As a result, CP systems will continue to work efficiently, and pipelines plus personnel will be safe from undesirable AC interference.
Challenge #2: Interference Mitigation
To understand the extent of corrosion and pipeline integrity, interference surveys are essential. Pipeline infrastructure have stated interference limits and mitigative measures are required to reduce external corrosion risk, thereby preventing costly infrastructure damage while lessening the risk to personnel and reduced 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, power line re-conductoring, adding additional power 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. 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 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 path to ground 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.
