In April 2018, California curtailed a record 94,805 MWh of renewable energy, which is enough energy to power approximately 30 million homes for an hour.¹ Similar challenges are being faced by grid operators around the world where the growth of renewable energy is outpacing the capacity on the grid, resulting in higher energy costs and wasted energy production. Without new tools to increase the flexibility and capacity of the grid, large amounts of renewable energy may never make its way to the grid because of overhead line traffic jams limiting the flow of power.
Use what you have, but use it smarter
New overhead lines are certainly part of the solution. Renewable generation is frequently concentrated in regions far from load centers and more capacity is needed as new projects come online. But building new overhead line infrastructure is costly, runs up against zoning challenges and can take decades to complete. And it doesn’t address the immediate problem of what to do with all of the renewable energy stuck in the grid equivalent of a Los Angeles rush hour.
Fortunately, tools exist today for utilities to manage their existing overhead line assets more dynamically and efficiently – making additional “lanes” on their existing overhead line highways available when they are needed most. Overhead line monitoring uses advanced sensors and analytics to give utilities greater visibility into the real-time status of the grid and make it more flexible to reliably handle the dynamic and variable nature of renewable energy.
Overhead line monitoring unlocks additional capacity within the existing infrastructure because it allows utilities to operate their lines based upon forecasted and real-time data. This combination of forecasted and real-time data more accurately reveals the safe and reliable operating limit of a line as compared to utilizing a static limit with extremely conservative assumptions. The use of dynamic line rating (DLR) can unlock as much as 40 percent more overhead lines capacity on existing lines.²
Can you take the heat?
Dynamic line rating, which is also known as real-time dynamic thermal rating, is used to increase the capacity on congested lines by determining the temperature of the power line and comparing that value to its maximum operating temperature to know how much more carrying capacity the line can safely take. LineVision’s non-contact sensors are mounted to overhead line structures, meaning lower implementation costs and a faster installation time than conductor-mounted sensors. These sensors analyze variables including the electrical current flow through the line, the sag and horizontal motion of each individual conductor and weather conditions such as wind speed and direction.
LineVision follows the industry-accepted IEEE 738 standard line rating methodology to calculate dynamic line ratings. The incremental capacity results from the fact that actual weather conditions are generally much more favorable than the worst-case weather assumptions used for traditional static ratings. Wind is the biggest factor, and a nominal increase in wind speed over the static rating assumptions, for example, can have a significant impact on cooling the line so that it can carry more electrical capacity. An additional 0.914 m/s (3 ft/s) at a 45° angle to the overhead line has been shown to increase its capacity by 35 percent, and by 44 percent when perpendicular to the line.³ For utilities, this additional capacity on highly congested lines can translate into significant reduction in congestion costs and renewables curtailments. LineVision and PJM recently conducted a pilot project that realized over $4 million in savings per year in congestion costs.4
Download our one-pager on all the benefits of overhead line monitoring to learn more about how LineVision’s non-contact overhead line monitoring can help utilities unleash the grid’s full potential.
1. U.S. Department of Energy, “Dynamic Line Rating Systems for Transmission Lines Topical Report”, April 25, 2014.
2. S. Murphy & al. “Simulating the Economic Impact of a Dynamic Line Rating Project in a Regional Transmission Operator (RTO) Environment”, CIGRE Grid of the Future 2018.
3. U.S. Department of Energy, “Dynamic Line Rating Systems for Transmission Lines Topical Report”, April 25, 2014.
4. S. Murphy & al. “Simulating the Economic Impact of a Dynamic Line Rating Project in a Regional Transmission Operator (RTO) Environment”, CIGRE Grid of the Future 2018.Back to Blog