Managing Aging Infrastructure
The aging condition of the U.S. transmission and distribution grid will require investment well into the next decade. Across the U.S., transmission and distribution lines and substations are nearing the end of their useful lives. According to the American Society of Civil Engineers 2017 Infrastructure Report Card, “most electric transmission and distribution lines were constructed in the 1950s and 1960s with a 50-year life expectancy.” The average age of AEP’s transmission lines is 48 years and the average age of transmission transformers is 37 years. Some transmission line facilities still in use today were put in service as far back as 100 years ago.
On AEP’s distribution system, the average age of distribution poles is 32 years, and the expected life is 45 years. Throughout AEP’s service territory, there are over 86,000 miles of small conductors that are at least 40 years old and are in need of upgrade. Re-conductoring these lines will improve capacity and reliability, and can facilitate connecting circuits together to automate them.
The Report Card also says that without greater attention to aging equipment, “Americans will likely experience longer and more frequent power interruptions.” To prevent this from happening, AEP is taking a number of steps and making investments to upgrade the power grid.
For example, we conducted a system-wide review of our transmission grid to identify those transmission facilities with performance conditions and risk of failure that warrant upgrade or replacement. We prioritize projects based on several factors to ensure that dollars are invested where they are most needed.
The investments we are making to modernize the grid will improve reliability and resilience, as well as lower the age of the system. Here are examples of how our investments are making a difference for customers:
In Michigan’s Kalamazoo County, an approximately $30 million transmission project to build a new substation and transmission line will significantly improve reliability to the area. The Vicksburg-Schoolcraft area improvements are essential due to frequent power outages and interruptions caused by the 1970s vintage substation serving the region. Over the last three years, the older line and substation were the cause of approximately 5 million customer minutes of interruption per year.
In West Virginia, a project is underway to upgrade the transmission system in four counties to replace aging infrastructure and improve reliability. The Meadow Bridge Transmission Line Upgrade in Fayette and Greenbrier counties, Carbondale Transmission Line Upgrade in Kanawha and Fayette counties and Pineville Area Power Improvements in Wyoming County will involve rebuilding more than 50 miles of transmission line and upgrading substations. Replacing the aging infrastructure, which has caused over 13 million customer minutes of interruption over a three-year period (2013-2016), will reduce outages, make the system more resilient and improve restoration times.
In Arkansas, SWEPCO is rebuilding approximately 19 miles of existing 69-kilovolt transmission line in Scott and Sebastian counties. The estimated $19 million North Huntington – Waldron Transmission Line Rebuild Project will replace old wooden poles and transmission line with single steel poles and new conductor. This line has contributed to the second-most customer minutes of interruption in the past decade in SWEPCO’s service territory.
Asset Health Center
Real-time performance monitors installed and managed by the AEP Transmission Asset Health Center (AHC) have enabled us to swiftly prevent transformer failures, saving the company up to $20 million, plus the time to install a replacement. The AHC is one example of AEP’s early adoption of digital technology to improve grid efficiency and reliability through proactive and predictive maintenance of our physical infrastructure.
There are two main components to the AHC – an analytical software platform with algorithms that provide health indices, risks of failure, and actionable notifications; and a fleet-wide installation of asset monitoring devices that provide instantaneous data through a robust communication infrastructure, allowing us to monitor the system in real-time.
In 2017, several accomplishments were credited to the AHC project, including deployment of monitoring on 107 extra-high voltage transformers/reactors; creation of a standard for circuit breaker monitoring; and partial discharge monitoring on underground cables. We have integrated AHC information with our Reliability Analysis Tool to allow for more informed decision-making on asset renewal and asset replacements. This helps to ensure we are making the right investments in the right places to replace aging transmission infrastructure proactively.
We are able to manage this as part of a regional reliability project portfolio. In addition, the AHC data has helped us to reduce safety risks to our employees in the field because we can identify safety risks in real-time. The transmission team is now working with predictive algorithms and the data collected from our sensors to see if we can anticipate equipment failures sooner.
In early 2018, AEP Transmission engineers authored a white paper outlining how the company is using the AHC to help design and operate the grid of the future. CIGRE, the Council on Large Electric Systems, which is an international organization that promotes global collaboration to improve electric power systems of today and tomorrow, recognized the AEP team with its 2017 CIGRE Grand Prize for the importance of the AHC to the industry.