html{display:none} SEL-RPM Redundant Power Module | Schweitzer Engineering Laboratories


Redundant Power Module

The SEL-RPM combines as many as three ac sources and one dc source to provide a single reliable dc output (unregulated 125 Vdc) to power your protection, monitoring, and control equipment. Large energy storage capacitors provide ride-through capability and support switch or breaker trip/close applications when all input sources are lost.

Ride-Through Calculators

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Improved Substation Power Availability and Reliability—By combining multiple sources, the SEL-RPM relies on control power diversity to keep protection, monitoring, and control equipment running during the loss of any single source. A momentary interruption can cause a much longer loss of device availability. The module’s reliable unregulated 125 Vdc output helps reduce device restarts and enables equipment to continue operating.

Ride-Through Capability—Large energy storage capacitors allow the SEL-RPM to provide significant ride-through time for equipment when all input sources are lost, enabling continued operation through momentary power interruptions. The SEL-RPM provides 50 seconds (nominal) of ride through for a 25 W connected load.

Breaker Tripping—The SEL-RPM allows protection and control equipment to trip breakers before running out of energy in the event of a total loss of power supply. It provides 100 W continuous and 30 A momentary surge current to trip breakers. Even without any energized sources, the SEL-RPM capacitors provide 1,300 watt-seconds (nominal) of energy for tripping purposes.

Ease of Use—The SEL-RPM has no jumpers or settings, making it simple to use. It is also maintenance-free because there are no batteries, firmware, or other components that wear out or need attention. You can install one SEL-RPM in the empty section of each panel to power multiple relays. It provides the source diversity of a dual battery system without the high costs of installing and maintaining a second battery system.

Control Power Source Diversity

The SEL-RPM has one dc input and three isolated ac inputs, allowing you to connect to diverse power sources in any combination. From there, you get a single reliable unregulated 125 Vdc output to increase device availability.



Multisource Power Module

The SEL-RPM combines multiple power control sources (e.g., a dc battery, station service, and backup generator) via three ac inputs and one dc input. The diversity of control power sources, especially in stations without batteries, increases the reliability of your control power. In the event of a disturbance on one source, the other sources continue to provide uninterrupted control power through the SEL-RPM.

Ride-Through Capability

With 126 mF of capacitance, the SEL-RPM allows protective relays, computers, and automation controllers to continue operating through momentary power interruptions. The ride-through time is dependent on the connected load and the connected device dropout voltage. The typical ride-through time for a protection panel with four feeder relays during normal operation is 50 seconds. For an automation panel, the typical ride-through time is 30 seconds during normal operation. To increase the ride-through time, you can install and operate multiple SEL-RPM modules in parallel.

Operation During Power Loss

Because the SEL-RPM allows equipment to continue operating when control power is lost, you can:

  • Size the ride-through capacity to allow transfer switch operation, backup generator starting, or automatic reclosing.
  • Program the breaker to trip when all input sources are lost.
  • Build “trip on loss of control power” and other safety schemes.
  • Power your relays long enough to trip breakers and store event records.


Introducing the SEL Redundant Power Module

SEL Redundant Power Module: Uninterrupted Ride Through During Power Failures

The Firmware IDs for older versions of the firmware can typically be found in Appendix A of the instruction manual.

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