High-Pressure Fluid Filled (HPFF) pipe-type cables are one of the most common designs—especially in urban environments—for underground power transmission systems. These trusted systems have delivered power to areas that cannot have above-ground high voltage wires for more than 50 years.
However, 50+ years of reliable delivery means these systems are aging—and require long-term, cost-effective repair solutions.
Let’s discuss two effective methods of repairing HPFF pipe-type cables:
1. External welded repairs
2. Carbon fiber composite reinforcement
While effective for small-scale repairs, external welded repairs are not ideal for larger repairs.
Pipe-type cables are at risk of leaking when the external coating exceeds its service life and environmental factors continue to wear on the pipes. When performing external welded repairs, a new coating must be installed to avoid interfering with the system’s cathodic protection.
Carbon fiber repairs are excellent solutions for high-voltage pipe-type cable repairs because they can be applied over the existing coating without risk to the system. Carbon fiber repairs:
1. Are high-strength
2. Add minimal weight to the system
3. Can be applied while feeder lines are in service
4. Allow heat dissipation through the pipe wall (critical for underground feeder lines) 5. Significantly reduce surface prep time compared to welded repairs
Unique approaches to application, such as our adhesion zone approach, streamline application time. The adhesion zone process enables only a small portion (about 6%) of the original coating to be removed to perform the repair. This process provides a structurally independent pipe and is applicable for up to 100% wall loss. It is recommended for sections of pipe where the coating is hazardous and/or hard to remove. Additionally, no service interruption is required to perform the repair.
Project Highlight:
Advanced FRP has performed exhaustive third-party testing to validate the effectiveness of composite repairs for pipe-type cable reinforcement. These tests include both thermal testing and pressure testing with through-wall failures present, up to 1000psi.
Composite Repair of Underground Power Transmission Lines
High-Pressure Fluid Filled (HPFF) pipe-type cables are one of the most common designs—especially in urban environments—for underground power transmission systems. These trusted systems have delivered power to areas that cannot have above-ground high voltage wires for more than 50 years.
However, 50+ years of reliable delivery means these systems are aging—and require long-term, cost-effective repair solutions.
Let’s discuss two effective methods of repairing HPFF pipe-type cables:
1. External welded repairs
2. Carbon fiber composite reinforcement
While effective for small-scale repairs, external welded repairs are not ideal for larger repairs.
Pipe-type cables are at risk of leaking when the external coating exceeds its service life and environmental factors continue to wear on the pipes. When performing external welded repairs, a new coating must be installed to avoid interfering with the system’s cathodic protection.
Carbon fiber repairs are excellent solutions for high-voltage pipe-type cable repairs because they can be applied over the existing coating without risk to the system. Carbon fiber repairs:
1. Are high-strength
2. Add minimal weight to the system
3. Can be applied while feeder lines are in service
4. Allow heat dissipation through the pipe wall (critical for underground feeder lines) 5. Significantly reduce surface prep time compared to welded repairs
Unique approaches to application, such as our adhesion zone approach, streamline application time. The adhesion zone process enables only a small portion (about 6%) of the original coating to be removed to perform the repair. This process provides a structurally independent pipe and is applicable for up to 100% wall loss. It is recommended for sections of pipe where the coating is hazardous and/or hard to remove. Additionally, no service interruption is required to perform the repair.
Project Highlight:
Advanced FRP has performed exhaustive third-party testing to validate the effectiveness of composite repairs for pipe-type cable reinforcement. These tests include both thermal testing and pressure testing with through-wall failures present, up to 1000psi.
Learn how composite solutions can improve the reliability and efficiency of your system. Schedule your free consultation today: https://www.advancedfrpsystems.com/free-consultation/
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