Instruction Manual
Table Of Contents
- Major Features and Benefits
- Functional Overview
- System Overview
- Application Examples
- Collect Fault Information From Remote Branches
- Improve Fuse Coordination
- Fuse-Blowing Scheme Shortcomings
- Improve Fuse-Blowing Schemes With the Fault Transmitter and Receiver System
- Fuse-Saving Combined With Fuse-Blowing Schemes
- Improve Feeder Cable First-Span Protection
- Implement a Low-Cost Fast Bus-Tripping Scheme
- Tripping the Right Recloser Faster
- Safety Information
- Network Deployment Overview
- Device Installation
- Dimensions
- Specifications
- Appendix A: Manual Versions
- Appendix B: Two-Branch Application
- Appendix C: Link Budget Analysis
- Appendix D: SEL-RP50 Fault Repeater Detailed Implementation
- Technical Support
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Date Code 20210405 Instruction Manual SEL-FT50/SEL-FR12 Fault Transmitter and Receiver System
Application Examples
You can find further details in Low-Cost Fast Bus Tripping Scheme Using High-
Speed Wireless Protection Sensors (presented at WPRC, October 2018) and SEL
application guide Using the SEL-FT50/SEL-FR12 System to Selectively Block
Fuse-Saving and Accelerated Tripping in the SEL-351R Recloser Control
(AG2018-14), both available at selinc.com.
Tripping the Right Recloser Faster
You can protect a distribution feeder with multiple reclosers. In a radial system,
to optimize selectivity, users want the recloser closest to the fault to operate for
that fault. For this reason, reclosers at the end of the distribution line are set to
trip first and the close-in reclosers are set to delay their tripping.
Figure 13 shows a fault in Zone R1. In a conventional protection design, assum-
ing the reclosers use a fuse-blowing scheme, R1 clears this fault, but only after it
gives Zones R2, R3, and R4 a chance to operate. This situation results in a long
fault duration that stresses the system and impacts the power quality on other
substation loads.
Fix this problem by using an SEL-FT50/SEL-FR12 system. In Figure 13, the
SEL-FT50 detects the fault and immediately transmits the information to the
SEL-FR12, which then sends this information to the recloser control at R1.
Because R1 knows that the fault is in its zone, it trips without waiting for the
downstream reclosers, avoiding the unnecessary coordination delay.
Figure 12 Wireless Fast Bus-Tripping Scheme
SEL-FT50
SEL-FR12
SEL-FT50
SEL-FT50
SEL-FT50
Bus Relay
F2
F1
Bus
R2R1 R3 R4
Figure 13 Radial Distribution Line With Multiple Reclosers
R1
SEL-FR12
SEL-651R-2
R2
R3 R4
SEL-FT50