Motor Protection Relay

Protect asynchronous (induction) and synchronous motors with one SEL-710-5 Motor Protection Relay. Features include broken rotor bar detection and variable-frequency drive (VFD) support as well as options for arc-flash detection (AFD), differential protection, and synchronous motor protection. The synchronous option supports power factor regulation and includes, at no additional cost, a voltage divider accessory to interface with the motor excitation system.

An optional 5-inch, 800 × 480 color touchscreen display allows you to directly set, monitor and control your system, including up to five two- or three-position disconnect switches. You can quickly integrate the SEL-710-5 into serial-or Ethernet-based communications schemes with IEC 61850 Edition 2, IEC 60870-5-103, the IEC 62439 Parallel Redundancy Protocol (PRP), Mirrored Bits communications, Modbus, DNP3, EtherNet/IP, the IEEE 1588 Precision Time Protocol (PTP), and other protocols. Together with the industry’s best AccuTrack Thermal Model, these features provide a great solution for all of your motor protection applications.

Applications

Motor Protection—Protect a full range of medium-voltage, three-phase induction and synchronous motors. The slip-dependent thermal model (AccuTrack) allows independent thermal protection of both the rotor and stator.

Arc-Flash Mitigation—Select optional arc-flash detection (AFD) inputs for overcurrent-supervised arc-flash protection. Reduce incident energy further by selecting high-speed, high-current interrupting output contacts to achieve secure, reliable, and fast arc-flash tripping.

Differential Protection—Configure current differential elements for more comprehensive protection of large, high-value motors.

Broken Rotor Bar Detection—Detect broken rotor bars in squirrel-cage induction motors by implementing the optional spectrum analysis features. Minimize repair costs and downtime by detecting rotor bar problems before they cause catastrophic motor failure.

Reliable Protection in Harsh Environments—The SEL-710-5 operates in extreme conditions, with an operating temperature of –40° to +85°C (–40° to +185°F), and it is designed and tested to exceed applicable standards, including vibration, electromagnetic compatibility, and adverse environmental conditions. In addition, the SEL-710-5 is ATEX-certified and Underwriters Laboratories (UL) Class I, Division 2-certified for use in hazardous and potentially explosive environments.

Synchronous Motors—Protect synchronous motors (brush and brushless). Use the optional inputs for measuring and controlling excitation system signals on brushed motors. Regulate power factor using digital or analog outputs of the relay connected directly to the excitation system.

Front-Panel Flexibility—Improve functional control and situational awareness with the programmable auxiliary buttons, LEDs, and configurable labels.

Metering and Monitoring—Analyze SER reports and oscillographic event reports for rapid commissioning, testing, and post-fault diagnostics. Use the SEL-710-5 Relay’s motor start report, motor start trending, load profile monitoring, motor operating statistics, and demand metering features to reduce separately mounted metering/monitoring devices.

Flexible Communications—Choose from single or dual ports, copper or fiber-optic Ethernet or serial communications, and several protocols, including IEC 61850 Edition 2, EtherNet/IP, IEC 60870-5-103, IEEE 1588 PTP, PRP, Mirrored Bits communications, DNP3 serial, and DNP3 LAN/WAN. You can select from multiple Modbus TCP or Modbus serial sessions for custom configuration of your application.

Asset Monitoring—Reduce production losses from unexpected equipment failures and lower maintenance costs by switching to predefined maintenance schedules. The SEL-710-5 can track the operating characteristics of your motor and accompanying devices with the built-in asset monitoring capability. You can monitor items such as vibration, motor start current, motor start times, motor stop times, broken rotor bars, incipient cable faults, and excessive wear on molded-case circuit breakers.