SEL-551 Overcurrent/Reclosing Relay
The SEL-551 Overcurrent/Reclosing Relay replaces the many relays, control switches, and wiring required in traditional distribution substation protection and control panels. The relay also replaces line recloser control packages at a fraction of the cost.
- Comprehensive Overcurrent Protection
Phase, negative-sequence, residual ground, and neutral overcurrent protection in a compact package. Complete set of instantaneous, definite-time, and time-overcurrent elements. - Reclosing
Program up to four shots of reclosing with sequence coordination logic for coordination with downstream reclosers. - acSELerator QuickSet® SEL-5030 Software Helps speed relay application by allowing you to develop relay settings off-line, program SELogic® control equations, and analyze post-fault event reports.
- Protection and Control LogicSELogic control equations with SELogic variables and timers allow traditional or advanced protection schemes. Programmable local control elements permit front-panel pushbutton control. Programmable text display points provide enhanced local operator information.
- Monitoring and Reporting
Instantaneous, peak, and demand metering. The latest twenty 15-cycle oscillographic data event reports and the latest 256 Sequential Events Recorder (SER) records are stored in nonvolatile memory. - Communications
ASCII, binary, and Modbus® RTU protocols enhance integration capabilities.
- Protect distribution feeders, distribution buses, transformers, capacitors, and circuit breakers.
- Select the "fast bus" trip scheme when protecting a distribution bus.
- Choose "fast" or "slow" curve operation to allow for cold load pickup.
- Connect the separate neutral current input to accommodate core-balance current transformers, separate neutral current transformers, tertiary winding current transformers, or CT ground residual circuits.
- Use SEL-5040 acSELerator Report Server™ Software to automatically gather relay event reports on your PC and manage them with a database.
- Use SEL-5010 Relay Assistant Software to manage your relay settings.
- Use SEL-5601 acSELerator Analytic Assistant™ Software to display oscillograms and vector diagrams to analyze event reports.
- Panel-mount or rack-mount hardware package.
- Connectorized packaging includes high-current interrupting output contacts.
- EIA-232 or EIA-485 serial communications — either port includes a demodulated IRIG-B time-code input.
- Bracket with mounting hole for FT-1 switch (switch not included) to mount one 500 series relay in a 19-inch rack.
Conformal Coating—Protect equipment from harsh environments and airborne contaminants such as hydrogen sulfide, chlorine, salt, and moisture.
Learn more about conformal coating.
SEL provides options to help you efficiently and safely commission and test these relays.
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Streamline commissioning by using the SEL-4391 Data Courier® to send and retrieve settings, gather event reports, and install enhancements.
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When access to the back of panels and cabinets is allowed, use a Connectorized® version of this relay for fast installation and testing.
- SEL accessories simplify operation and enhance the flexibility of SEL products.
- Add independent breaker control to any relay. The SEL-9510 Control Switch Module easily installs in panel or rack locations for independent local control and status indications.
Flyers
Data Sheets
Guideform Specification
Instruction Manuals
Settings Sheets
Application Guides
Case Studies
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