Threats to Grid Resilience
In the last decades, demands and threats to power grids have morphed and grown. Efforts to shore up grid resilience range from gradually replacing aging parts and increasing physical protection to improving monitoring technologies. Faster and more accurate fault detection leads to faster intervention and preventive actions. The information provided by current monitoring, such as fault recorders is ill-suited to report on the ground conditions with precision. The cost of line and tower-mounted sensor deployment and maintenance limits the number of sensors, and the discrete information they send routinely fails to account for actual conditions, leading to inefficient use of grid capacity. When freezing weather translates into surges in heating consumption, the risk of power outages rises exactly at the time power is most needed.
Aging Infrastructure
Built predominantly in the 1960s-1970s, the U.S. power transmission infrastructure is inadequate to accommodate the current demand and extreme weather events. 70% of its transmission lines are over 25 years old and are approaching their maximum 50-80 years service lifecycle. At transmission line junctions, tens of thousands of substation parts urgently need replacement.
Growing Energy Demands Strain the Grid Structure
High computing demand from AI and data centers, the growing adoption of electric vehicles and the widespread electrification of common appliances stretch the grid resilience. Renewable power sources are a welcome additional power input but their output fluctuates with weather conditions.
With the increased demand for electricity and the multiplication of power sources, the grids become so dispersed that it adds to their fragility. Balancing these new power sources and more costly traditional fossil fuel power plants increases grid management complexity.
Weather Impact
Of all major U.S. power outages reported from 2000 to 2023, 80% (1,755) were due to weather. Most weather-related outages were caused by severe weather (58%), winter storms (23%), and tropical cyclones including hurricanes (14%).
When weather events persist for days or are separated by short intervals, it exacerbates the strain on the grid’s infrastructure. They interfere with repair work, which prolongs the duration of outages, sometimes leaving people without power for days. For example:
- Texas, February 2021: Three consecutive winter storms in a short time created widespread outages. Over 4.5 million homes and businesses were cut off from electricity, some for several days.
- Snohomish County, Washington, November 2022: a windstorm with wind speeds up to 80 mph caused short and long outages to 365,000 households and businesses, about half of the county’s population
- Central and Eastern U.S, Christmas 2022, winter storm Elliot: Widespread outages left 1.7 million households and businesses without power for extended times. About 13.33 million people across Texas, Florida, Arkansas, Tennessee, West Virginia, and Wisconsin also suffered from outages for shorter periods.
These extended power cuts coinciding with freezing temperatures directly or indirectly endanger lives as people are left without heating in freezing temperatures. Some try to keep warm in their car, with smoke inhalation risks; some opt to brave the blizzard, despite icy winds and risks of falling trees, to reach places with heating. It is often difficult to evaluate the exact number of casualties directly or indirectly due to power cuts, but it is safe to assume that, during extreme weather events, the sudden lack of access to electricity-powered devices increases risks.
In winter, several factors push the grid resilience to, and beyond, its limits. Those range from the compounding effects of snow and ice build up – a mere half an inch (1.5 cm) ice accumulation on a transmission line adds 500 pounds (1100 kg) weight, worsened by snow build up. The added weight stresses the lines and the support structures weaken. The ice-induced sag turning the ice surface into a giant sail increases the risk of galloping lines.
Case Study: New York Winter 2023
Winter 2023 record-breaking snowfalls and freezing temperatures across New York strained its power grid. Millions of residents trusted the New York Power Authority (NYPA) to keep the lights, and the heating, on. Testing the grid resilience, transmission lines sagged under the weight of ice. Asymmetric ice deposit on the cable affected their shape, which increased the risk of galloping line events.
In 2021, to find a solution that would prevent or at least minimize weather event-induced outages, NYPA turned to Prisma Photonics’ optical fiber sensing technology. One of the key elements to limit outages is the ability to react fast and accurately to signs of stress to grid resilience. Traditional line and power-mounted discrete sensors are too far apart to locate grid resilience threats precisely. The information they provide misses out on localized events in the long intervals between sensors, and they send that information at intervals as the fixed conditions determine. Prisma Photonics optic-based sensors, on the other hand, provide continuous information, both in time and pinpointing problems location to the closest tower. to buttress its grid infrastructure, address immediate weather-related risks, and lay the groundwork for long-term resilience.
- Icing Detection: Optical fiber sensing systems detect ice accumulation as it is formed and show the exact location of stressed spans requiring intervention. Operators can send repair teams from the control room exactly where they are needed.
- Wind and Galloping Lines Monitoring: The continuous inflow of data on wind magnitude and direction is analyzed to identify weakened and stressed transmission spans in time to send repair teams before further damages cause outages.
- Enhanced Operational Efficiency: The collected data can also lead to dynamically adjusted line ratings and maximized use of the existing infrastructure, which reduces the need for costly upgrades – in winter or summer.
Failure to identify and precisely locate operational stress or weaknesses in time magnifies the grid’s struggle to keep Christmas lights on.
Advanced Monitoring Capabilities
Optical fiber sensing monitoring capabilities measure acoustic and strain variations in vibrations due to various events, such as suspicious variations of the transmission lines’ temperature, short circuits, and people’s activity near power towers. This continuous monitoring detects issues stemming from line stress, structural anomalies, or weather-induced effects as they happen.
AI for Enhanced Data Correlation
Artificial intelligence (AI) analysis of the data identifies patterns and faults. Its predictive analytics inform grid operators in time to allocate resources where they are most needed. The immediate analysis of detected issues that threaten the grid’s resilience, operators can send repair teams before those issues escalate into serious damage.
Lessons from Implementation
Scalability and Simplicity
Prisma Photonics’ optical fiber sensing technology demonstrates exceptional scalability. Using Optical Ground Wire (OPGW) infrastructure avoids the need for expensive hardware installations. Prisma Photonics’ systems have been deployed across hundreds of kilometers using substation-based installation with neither disruption nor downtime. Even if two substations are tens of miles apart, optical interrogator units can be installed in a substation’s communications room, sometimes within a day.
Enhanced Monitoring
Prisma Photonics’ granular, span-by-span transmission line system monitors the grid’s resilience by measuring acoustic vibration, seismic signals, temperature shifts, and acoustic anomalies. This detects issues such as mechanical faults, icing, wind or ice-induced galloping lines, and wildfire temperature-induced stress that traditional systems would overlook. Electrical faults, such as short circuits and flashovers, can be alerted, pinpointing the tower where the fault occurred.
Predictive Maintenance
The Prisma Photonics platform’s combination of data inputs and AI analytics detects and locates partial discharges or coronas, which occur over time and may damage assets and lead to arcing and further damage. Pointing to increased corona status can direct ground patrols to the right towers instead of a long sweeping cleaning or maintenance activity across an entire line. The derived data enable predictive insights, reduce repair times, prevent outages, and significantly extend grid asset lifecycles.
Learn more about Prisma Photonics’ Climate solution and how it can fortify your grid’s resilience.
