GE Grid Solutions is discontinuing several relays from its Multilin SR family of products. These microprocessor-based multi-functional relays were widely used around the turn of the century for industrial protection and management applications in industrial environments, data centers, electrical service entrances, distributed generation (DG) interconnects, motors, transformers, and generators. Instead of requiring a relay for each function, these first-generation solid-state relays allowed customers to consolidate multiple functions into a single platform.
This year GE announced, “manufacturing of SR750/760, SR469, SR745 and SR 489 will be discontinued on 1st of January 2020 due to the unavailability of critical components used within the product.”
GE recommends its Multilin 8 Series “next-generation protection and control relay platform,” launched in 2013, as an equivalent replacement. The 8 Series provides comprehensive protection and asset monitoring for critical feeders, motors, generators, and transformers. It also offers substantial improvements to longevity and reliability over previous models, with features like field-swappable power supplies that don’t use electrolytic capacitors for energy storage. 8 Series also achieves a sampling rate of 128 samples/second compared to the SR’s 16 samples/second.
|SR750/760 (feeder management)||850|
|SR469 (motor protection)||869|
|SR745 (transformer management)||845|
|SR489 (generator management)||889|
While the enclosure cut-out dimensions are the same as the Multilin SR relays, 8 Series relays have different pinouts that may require terminals to be rewired. In some cases, existing wire lengths may not be sufficient. GE offers a Multilin 8 Series Retrofit Kit, which includes a depth reduction collar and a factory-wired terminal block that accurately maps the existing 750/760 terminal locations to the new 850 terminal block.
Options for Customers with Affected Relays
- Do nothing
Since GE will continue supporting these relays for 10 years from July 1, 2019, this is a viable short-term option, but customers should begin planning a transition from these devices.
- Purchase spares
GE is offering a last-time-to-buy window until June 29th, 2019, and will continue to honor repair or replacement warranties for at least 10 years.
- Upgrade affected relays
For customers wanting to upgrade, GE recommends its 8 Series relays, which offer advances in protection, control, automation, and communications, and are compliant with NERC-CIP standards for cyber security.
- Retrofit to another manufacturer’s relay
While other products offer some valuable features and benefits, changing to a relay from a different manufacturer requires that the switchgear door be replaced and the new relay be reprogrammed; for complex installations where the programming is more complicated, the switchgear should also be recommissioned.
- Equivalent “replacement” relays convert settings files from existing relays regardless of firmware or software version
- If using the GE 850 adaptor kit, the new enclosure will project an additional inch from the switchgear door, or extend an inch deeper inside the switchgear
- It’s important to note that since the 5A secondary transformers residing within the SR Multilin relays are now installed in the 8 Series relay case, when testing the new relays in a test case, the actual secondary transformers are not being tested – we recommend an in-service load check for new relays
- Because the Multilin SR relay power supplies have electrolytic capacitors that don’t operate well after remaining uncharged for over a year, stockpiling replacement relays should only be considered if they can be energized periodically
So, Where Do You Go from Here?
The road you take depends on several factors including immediate and long-term needs and priorities, costs and budgetary considerations, equipment and system configurations, and other relevant variables. An on-site facility assessment is a valuable first step towards determining the best course of action, as it can provide insight, collect needed information, and highlight concerns crucial to determining the best path forward for your specific facility.
If you decide to move forward with retrofitting the 8 Series replacement relays or another manufacturer’s device, you may also consider bringing in a knowledgeable consultant for help with:
- Relay settings data collection
- Relay programming and testing
- Engineering design and planning
- Procurement support
- Wiring diagrams
- MOP development
- Relay testing
- Integrated systems testing & commissioning
HP&D can help; contact us to discuss your options, arrange a facility assessment, or for information about our services and capabilities.