Robots & Sensors


Electric co-ops use innovative technologies for real-time
feedback on the GRID’s health.

Electric grids are immense machines that span counties, and often entire states, bringing power to many homes and businesses. So how do the electric companies know what’s happening on their lines? How much power is being delivered? What equipment needs to be replaced? These are important questions that electric cooperatives spend a lot of time and money to answer.

For many years, electric co-ops relied entirely on in-person inspections to determine asset conditions and calls from members to discover power outages. During and after storms, this could mean lengthy recovery times as supervisors evaluated the available information and decided where to send line crews, who then searched for damaged lines in order to make repairs and restore electric service. Even normal operations required personnel to be sent into the field constantly to perform manual inspections. Today, electric co-ops may choose from a wide array of technologies that give them near real-time feedback on the health of the grid. Monitoring and automation technologies are becoming more affordable and gaining more functionality leading to greater use in the field.
Two of the most common technologies in this space are Supervisory Control and Data Acquisition (SCADA) and Automated Meter Infrastructure (AMI).

Electric cooperatives are exploring a host of innovative technologies, such as smart meters and special sensors placed on power lines for niche applications, including fault location, power theft detection and asset management

SCADA systems have greatly evolved since their original development in the 1920s. Modern systems take advantage of communication, monitoring, and automation technologies to give utilities a real-time picture of how substations are performing and make changes as needed. At the end of the line, AMI, also known as smart meters, report back to the utility how much energy consumers use, often on a 15-minute basis. Utilities can “ping” these meters to determine if they’re still receiving power during storms or other types of outages.

Beyond AMI and SCADA, utilities are exploring a host of other sensor technologies for niche applications including fault location, power theft detection, and asset management. These applications are being enabled by a new wave of inexpensive sensors that cost one-tenth of what they did a decade ago. When a fault occurs on a transmission line (the large power lines that carry power from plants to substations), it creates transient waves on the lines. By placing special sensors on transmission lines and measuring the time when waves reach two of these sensors, the location of a fault can be accurately and quickly determined. This lets the utility know exactly where to send repair crews.

Across the whole U.S. electric industry, roughly $6 billion worth of electricity is stolen annually, which leads to higher prices for everyone except the thieves. Traditionally, one of the best tools for identifying power theft is visual inspection of meters for signs of tampering, but with AMI systems, utility personnel aren’t visiting meters in-person as often. Load-monitoring sensors—often called current transformers (CTs) or current sensors—can be placed on distribution power lines to help catch significant losses along a line, from theft or for other, more innocent reasons. Data gathered by CTs can be reconciled with meter readings to investigate discrepancies between the electricity passed through the line and the electricity measured by the meters. CT devices are also valuable for diagnosing excessive line loss due to other problems, such as conductor damage or aging transformers.

For co-op members, these technologies provide three primary benefits: increased reliability, reduced outage times, and lower prices as the utility manages employee time and resources more efficiently. As sensors continue to improve and drop in price, expect to see more real-time grid monitoring.

Thomas Kirk is an associate analyst of distributed energy resources for the Arlington, Va.-based National Rural Electric Cooperative Association’s Business & Technology Strategies (BTS) division.