P36.003: Laminar Dielectric Cable Systems

Objective

Laminar dielectric cable systems consist of high-pressure fluid-filled (HPFF), high-pressure gas-filled (HPGF), and self-contained fluid-filled (SCFF) system types. These cables in general have provided long-lasting service, surpassing their design life specifications. However, the advanced age of many of these assets might be a cause for concern. Replacement costs for laminar dielectric cable systems are high and the consequences of electrical failures or fluid leaks are significant. Research is needed to:

• Improve understanding of laminar dielectric cable system failure mechanisms.
• Develop and demonstrate inspection, diagnostic, monitoring, and remediation techniques.
• Provide guidance and develop strategies for effective operation, maintenance, life extension, and replacement.

Underground transmission engineers, designers, and managers may use the knowledge base, guidelines, methods, and technologies developed in this project to improve productivity, lower cost of operation and maintenance, and extend the life of laminar dielectric cable systems. Reliability and safety can be enhanced, and asset management strategies can be improved. Maintenance personnel can make more effective use of staff time and budget resources by applying new inspection methods and monitoring technologies. Planners may learn where to apply selective upgrades and retrofits through a better understanding of the relative conditions of their asset fleet, as well as where and under what circumstances cable systems are most susceptible to damage. In addition, utilities can apply the knowledge of corrosion mechanisms and detection to fine-tune the monitoring of their systems to enhance public and environmental safety.

Research Value

This research produces new understanding, methods, and tools that could improve the ability of engineers and planners to assess the condition of laminar dielectric cable systems and take proactive steps in operating and maintaining these systems to extend asset life and prevent unexpected outages. Benefits of this project may include:

• Better understanding of failure mechanisms and prevention procedures for longer asset life, fewer customer outages, and lower operations costs.
• Effective inspection and monitoring of assets, leading to increased asset utilization, rapid maintenance intervention prior to spontaneous failure, higher reliability, and lower repair costs.
• New inspection techniques and tools to increase staff productivity and reduce overall maintenance costs.

Planned 2025 Research

This project investigates and develops condition assessment methods and procedures for laminar dielectric cable systems. Efforts focus on life extension, improved reliability, reduced operation and maintenance costs, and improved support for asset management decision-making protocols. EPRI intends to direct its research at one or more of the following areas:

Evaluate and demonstrate advanced diagnostic techniques to assess conditions of laminar dielectric cables.

Develop best practices in dissolved gas analysis and insulating paper and fluid testing for effective deployment of the technologies.

Develop vintage information for laminar dielectric cable systems for improving asset management strategies.

Conduct investigations to better understand failure mechanisms of laminar dielectric cables.

Study buried steel pipe coating degradation as a function of coating types, coating ages, pipe installation environments, coating application methods, and stray current conditions.

Evaluate and develop methods to effectively detect and mitigate corrosion and corrosive environments.

Develop technical bases for best practices to improve the effectiveness of cathodic protection systems.

Anticipated Deliverables

Past EPRI Research on Topic