The challenges faced by electric power companies today are exponentially greater than they were just a few decades ago. Following WWI, as our population grew, Utilities built new electric generators, transmission lines, substations, and distribution grids. All was looking good. However, as population centers grew, it became increasingly difficult to site new generation and transmission assets. Space became limited and existing transmission lines became congested. While ‘new’ ACSS conductor technology (introduced in the 1970’s) could carry more current at elevated temperatures, it didn’t do much more than serve as a band-aid on a growing wound.
More recently, in the wake of more frequent and severe weather events - aka climate change - Utilities have been busy repairing damage from ongoing storm and fire events and ‘hardening’ the grid to protect it from future events. Concurrently, many Utilities are scrambling to secure permits to build and connect cleaner sources of generation.
Fortunately, a number of new technologies are available to help. These Grid Enhancing Technologies (“GETs”) include Dynamic Line Rating devices, Load Flow Controllers, Topology Optimization Software, and Advanced Conductors. The challenges are so substantial - and the success of the task so critical to the wellbeing of our population, economy, and environment - that the U.S. Government is making billions of dollars in funding available to support many Utility initiatives.
While all of these technologies are being deployed to improve the efficiency, capacity, reliability and resilience of the existing power grid, it is essential that they also serve as the foundation for building a new modern grid - and we’re really “down to the wire,” as the old expression goes.
The term “down to the wire” came from horseracing, where it was long the practice to stretch a wire across and above the track at the finish line. “Down to the wire” meant time was very quickly running out. Today, let’s assume the expression is aimed at the urgency of modernizing the electric power grid and consider why the use of Advanced Conductors ('modern wire') is so essential.
In 2003, at the dawn of the introduction of Advanced Conductors, the Northeastern United States and parts of Canada experienced a major blackout. During a record heatwave, when the system was highly stressed, out-of-calibration telemetry devices sent inaccurate data to a control center. Poor communications between grid operators and a computer reboot failure led to conductor overheating and sag trip outages on a 345 kV line that caused cascading sag trip outages on other 345 kV and 138 kV lines – completely shutting down the power grid. This outage lasted for several days stranding drivers in complete gridlock, hotel guests in elevators, and hospitals in darkness. Lives were lost and the region suffered an estimated $8 - $10 billion in losses. If high-capacity, low-sag Advanced Conductors had been in place, the event could have been avoided.
While Advanced Conductors are being deployed to increase the capacity and reliability of existing transmission lines to help accommodate N-1 conditions and mitigate sag infractions, their greater strength and toughness are also helping improve grid resilience.
In May 2013 an EF-5 tornado with winds estimated at 210 mph struck Moore, Oklahoma, crossing directly over a recently installed 138 kV ACCC® Conductor transmission line. A flying oil tank slammed into the side of a 125’ tall steel monopole, knocking it over by 45 degrees. The shockwave on the conductor was so severe that it severed the conductor’s aluminum strands in one area. Fortunately, the carbon fiber core was so strong that it didn’t break which allowed linemen in two bucket trucks to quickly splice in a 20’ section of conductor and quickly put the line back into service. If the core would have failed the conductor would have fallen to the ground and larger equipment and more time would have been required to complete the repair.
While the ACCC Conductor has survived numerous extreme weather events at more than 1,000 installations dating back to 2004, a wildfire in Nevada burned down several wood H-frame structures that had been reconductored with ACCC, dropping the steel cross arms, insulators and conductor to the ground. The utility was able to replace the wood poles and damaged insulators and pull the conductor back into place quickly.
These are just a few examples of resilience, but the attributes of Advanced Conductors go much further. As we strive to build a modern electric power grid to support decarbonization and electrification, shouldn’t we consider all available technologies?