Synchronized phasors (synchrophasors) provide a real-time measurement of electrical quantities from across the power system. Applications include wide-area control, system model validation, determining stability margins, maximizing stable system loading, islanding detection, system-wide disturbance recording, and visualization of dynamic system response. The basic system building blocks are GPS satellite-synchronized clocks, phasor measurement units (PMUs), a phasor data concentrator (PDC), communications equipment, and visualization software.

Why Choose SEL?

  • SEL has a comprehensive portfolio of products to create a complete solution that meets your needs.

  • SEL has experience implementing systems worldwide and guarantees products with a ten-year warranty.
  • SEL relays and meters include PMU capability free of charge. This makes SEL systems economical and easy to implement.
  • The SEL Engineering Services team can design, install, and commission your system to meet your schedule and budget.

See Live Synchrophasors and Try Software on Demand


SEL is streaming synchrophasor measurements from wall outlets across the United States to a demo version of SEL-5702 Synchrowave Operations. With your mySEL account, you can easily log in to this demo software to visualize live data and try out key features of Synchrowave Operations. 

The Synchrophasor Report

Learn from SEL experts about applications, advancements, techniques, and products to make the most of synchrophasors.

System Components

Synchrophasors are currently being used by utilities around the world for system model validation, situational awareness, stability analysis, islanding detection, disturbance analysis, and wide-area measurement and control. SEL offers a wide variety of solutions to fit your application. Whether you are working with individual units or a complete system, SEL can help you design, install, and commission your system.


  Format   Synchrophasor Data Elements
PMU IEEE C37.118 IEEE C37.118 Compliance Level SEL Fast Message Message Rate CT Inputs PT Inputs Analogs Digitals
SEL-2240 Axion—Modular PMU 2011 compliant P and M class 1–60 mps 64# 64# 64# 30
SEL-311C, SEL-351,
SEL-351A, and SEL-351S Protection Systems
1 1–60 mps 3 3 0 16
SEL-351RS Kestrel Single-Phase Recloser Control 1   1–60 mps 1 1 0 16
SEL-487V, SEL-421, and
SEL-451 Protection, Automation, and Control Systems; SEL-411L Advanced Line Differential Protection, Automation, and Control System
1 1–60 mps 6 6 16 64
SEL-487E Transformer Protection Relay 1 1–60 mps 18 6 16 64
SEL-651R-2 Recloser Control 1   1–60 mps 3 6 0 64
SEL-751 Feeder Protection Relay 1   1–60 mps 3 3 4 16
SEL-751A Feeder Protection Relay 01   1–10 mps 3 3 4 16
SEL-700G Generator Protection Relay 1   1–60 mps 6 6 4 16
SEL-787 Transformer Protection Relay 01   1–10 mps 6 3 4 16
SEL-787-3E/-3S/-4X Transformer Protection Relay* 1   1–60 mps 12 4 4 16
SEL-311A, SEL-311B,
SEL-311L, and Legacy SEL-351 Relays
    1 mpm–1 mps 3 3    
SEL-734 Revenue Meter   01 1–20 mps 3 3    
SEL-735 Power Quality and Revenue Meter 2011 compliant P class 1–60 mps 3 3 4 16
SEL-2431 Voltage Regulator Control 1   1–60 mps 1 2 0 8
SEL-400G Advanced Generator Protection System 2011 Compliant P Class Yes 1 -60 mps 18 6 16 64

1 Level 1 compliant for TVE and frequency range.
# A maximum of 64 CT, PT, or analog inputs allowed.
*12 CT inputs and the 4 PT inputs are maximum for each and a unit can not be configured with both of these maximums.

IEEE C37.118-2011 defines performance classes P and M. IEEE C37.118-2005 defines performance classes 0 and 1.

Questions? Contact Us!

If you have any questions about SEL products, services, solutions, or support, please contact us. Our service and support professionals are ready to provide the answers you need.

Unbeatable Support

SEL support teams are stationed in regional offices around the world and staffed with application engineers who are experts in our products and in power system applications.

Technical support for SEL-manufactured devices is always free. No matter how often you need to call or how long your SEL products have been in service, you’ll reach an SEL expert who can provide the service and support you need.

Our cybersecurity team is always ready with the information and resources needed to keep your OT networks and critical systems secure and working effectively. Cyber services support contracts can include incident response, audits, system hardening, and more, depending on your anticipated needs.

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