Reconductoring a transmission ROW in Phoenix: how SRP achieved an 80% capacity jump in 18 months

Phoenix is booming — and the grid is feeling it. The city is one of America's fastest-growing large cities for population and ranks among the top five US cities for data center load growth. 

All of this has already strained certain parts of the Salt River Project (SRP) system. Serving more than 2 million people in central Arizona, the not-for-profit utility knew it needed to modernize its approach. And reconductoring, with its promise of reusing existing infrastructure such as towers and current transmission rights of way (ROWs), seemed like a logical path forward. 

The problem? Traditional reconductoring approaches with legacy conductors often fell short. They either failed to deliver the capacity increases today’s grid requires, or they demanded costly infrastructure replacement that defeats the purpose of reusing existing assets. 

But SRP saw an opening. New breakthroughs in advanced conductor technology now make it possible to achieve performance that was once out of reach — dramatically increasing capacity without needing taller towers or specialized crews. SRP recently turned that potential into action. 

Reconductoring challenges rear their head 

In 2022, SRP faced a familiar utility dilemma on an 8.5-mile, 230 kV double-circuit line between the Orme and Rudd substations in suburban Phoenix. This line upgrade supports SRP system load growth in the area, including growing demand from residential customers, data centers, and industrial customers. 

But existing capacity — 2,210A continuous / 2,382A emergency — couldn’t keep pace with projected load growth requiring 3,800A / 4,180A emergency. This represented a roughly 80% capacity increase over the existing configuration. 

Given the scale of the upgrade and the surrounding environment, project constraints ruled out most conventional approaches to increasing capacity. The urban corridor ran through residential and commercial areas where ROW expansion wasn’t feasible. The existing 1970s-era tower structures still had an estimated 50 years of structural life — valuable assets that didn’t justify wholesale replacement, which would dramatically increase cost and the project timeline. 

At the same time, the existing double-circuit configuration — two-bundle 954 Rail ACSR (Aluminum Conductor Steel Reinforced) — was showing its age and thermal limitations. 

A new conductoring solution was clearly needed. 

But even traditional higher-capacity alternatives like ACSS (Aluminum Conductor Steel Supported) conductors presented problems: While capable of delivering the required ampacity on paper, their excessive thermal sag characteristics would violate clearance requirements — triggering structure replacement along nearly the entire 8.5-mile route.

SRP came into the project with hands-on experience from previous advanced conductor pilot deployments, including test spans on a 69 kV gen-tie line and three spans of carbon composite core conductor in areas with height restrictions. These installations gave the team valuable insight into installation practices and performance, directly informing the evaluation strategy.

With just 18 months from design to planned energization, SRP needed a solution that could work within existing infrastructure — and be ready before peak summer 2024 demand. 

AECC advanced conductors meet the moment 

Facing limited time, tight ROW constraints, and no margin for error, SRP approached the reconductoring effort as a high-stakes test of how far advanced conductors could stretch the limits of existing infrastructure. 

The utility issued a comprehensive RFP targeting high-temperature, low-sag (HTLS) manufacturers with specific requirements:
 

●     Minimum 3,800A continuous / 4,180A emergency ampacity

●     No tower modifications

●     Compatibility with standard installation practices

●     Fit within existing ROW profiles

The evaluation included engineering modeling using PLS-CAD simulations, physical validation through full-tension compression and vibration testing, and cost-benefit analysis comparing total project economics, including the value of preserving existing structures. 

While several options met the baseline performance thresholds, only TS Conductor’s double-bundled Cloudveil M3 offered the right combination of high ampacity, low sag, and full compatibility with SRP’s system and construction practices. 

Cloudveil M3 uses AECC (Aluminum Encapsulated Carbon Core) technology, a next-generation design that blends advanced conductor performance with the safety and reliability of traditional conductors. The conductor features a pre-tensioned carbon fiber core protected by an aluminum encapsulation layer, paired with annealed aluminum outer strands. 

This configuration delivers two to three times the capacity of ACSR using the same structures, cuts line losses in half, and maintains low thermal sag at high operating temperatures — addressing exactly the limitations that made ACSS unworkable for this project.

From design to delivery in record time 

Project execution followed conventional utility phases with design and preparation through April 2023, procurement partnerships with AFL for critical components, and phased construction from January to May 2024. Throughout, SRP maintained system reliability during installation. 

The reconductored line delivered exceptional results across all performance metrics:

• AECC technology provided the strength and low sag of carbon core designs, while its aluminum encapsulation ensured environmental protection and compatibility with standard compression fittings.
• Final continuous ampacity reached 3,978A — exceeding the 3,800A requirement.
• Emergency ampacity reached 4,226A, a 77% increase over original configuration.
• All clearance standards were met under operational load conditions. 

Thanks to strategic material selection, streamlined procurement, and effective project management, the project finished ahead of schedule at $10.1 million — nearly 12% under the original $11.5 million budget, representing a $1.4 million savings. 

Broader applications for grid modernization 

SRP’s experience highlights where reconductoring with advanced conductors delivers substantial value — particularly in:

• High-growth load zones requiring significant capacity increases.
• Urban corridors where structure replacement would cause major disruption.
• Systems with remaining infrastructure value and structural integrity.
• Projects facing tight timeline constraints that can’t accommodate extended construction schedules. 

This approach helps utilities modernize the grid without the disruption and expense of full-scale reconstruction — offering a replicable model for meeting today’s demands while preparing for tomorrow’s.