html{display:none} SEL Axion becomes first IEEE-certified PMU | Schweitzer Engineering Laboratories

SEL Axion becomes first IEEE-certified PMU


In this issue of The Synchrophasor Report, Isaac West, a power engineer, highlights a recent certification that distinguishes the SEL-2240 Axion as the first and only IEEE-certified phasor measurement unit (PMU) in the world.

Laying Foundations

For nearly two decades, SEL has maintained a keen focus on driving synchrophasor technology into the power industry. With the release of the first synchrophasor measurement-enabled protective relays in the early 2000s, SEL established itself as a leader in the PMU arena. Since the publication of the IEEE C37.118-2005 standard, SEL has continuously strived to comply with the latest synchrophasor standards. In 2013, SEL released the SEL-2245-4 AC Metering Module, a CT/PT metering module for the Axion that was the first SEL synchrophasor measurement technology to comply with the updated IEEE C37.118-2011 standard.

Figure 1. SEL Axion.

Clearing Hurdles

In 2015, IEEE invited SEL to participate in the IEEE Conformity Assessment Program (ICAP) for synchrophasors. The focus of this effort was to measure applicant PMU performance against the IEEE C37.118.1a-2014 standard for synchrophasor measurements. The Axion was SEL’s top choice for submission to ICAP.

On December 17, 2015, the SEL Axion was announced as the first PMU to meet the IEEE Standards Association (IEEE-SA) IEEE Synchrophasor Measurement Test Suite Specification—Version 2. To attain this certification, the Axion met or exceeded the rigorous requirements established by the IEEE Synchrophasor Conformity Assessment Steering Committee (SCASC), which consists of industry subject matter experts. Consumers Energy Laboratory Services, an IEEE-authorized independent laboratory, conducted the tests to verify compliance.

“Certification of the SEL-2240 Axion from a notable industry leader in power and energy, such as SEL, marks an important milestone for the IEEE Synchrophasor Certification program,” said Konstantinos Karachalios, managing director of IEEE-SA. “This program addresses a gap in the power industry by offering buyers of PMU technology a method to determine compliance of a product to the IEEE C37.118.1a standard before purchase and large-scale deployments.”

Going Modular

In addition to this recent certification, the Axion also includes several innovative features that make it SEL’s premier PMU:

  • Signal Processing
    The SEL-2245-4 AC Metering Module performs all of the necessary digital signal processing and filtering to provide premium synchrophasor measurements. This feature reduces the burden on the Axion and allows for optimal server performance (64 phasor quantities at 60 messages per second).
  • Scalability
    For distributed systems, the Axion can use multiple nodes for synchrophasor measurements with up to sixteen modules in a single system. This system becomes especially economical for larger schemes that require distributed synchrophasor measurements at separate locations.
  • Time Synchronization
    Deterministic communication between modules via the EtherCAT protocol allows the Axion to synchronize sampling for all synchrophasor measurements to within submicrosecond accuracy. Additionally, time synchronization between all modules reduces the need for multiple time sources in distributed systems.


SEL’s persistent advancement of power system technology continues to enable our customers to build more economical, finely tuned, robust solutions for critical power system applications. For more information about the Axion PMU, please visit the webpage or contact us using the form below.

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