Product information for the American SEL relay SEL-551 series

Brand

SEL/USA

Delivery Time

Over one month

Application Areas

Chemical, Petroleum, Mining, Energy, Road/Rail/Marine

SEL Relay SEL-551 (USA)

Overcurrent/Reclosing Relay

The SEL-551 overcurrent/reclosing relay replaces many relays, control switches, and wiring required for traditional distribution substation protection and control panels. This relay also replaces line recloser control packages at a very low cost.

Comparison of SEL Relay SEL-551/SEL-551C and SEL-851 (USA)

Asset Protection—Monitor and protect distribution feeders, distribution buses, transformers, capacitors, or circuit breakers.

Current Transformer (CT) Connection Versatility—Connect a separate neutral current input to accommodate core-balanced CTs, separate neutral CTs, tertiary winding CTs, or CT-grounded residual circuits.

Reclosing Control—Use sequence coordination logic to coordinate with downstream reclosers, programmable for up to four reclosing attempts. Field-proven robustness — SELogic control equation inputs and outputs can be programmed to meet application requirements in a variety of environments. A wide operating temperature range (–40°C to +85°C) allows for installation in control rooms or outdoor cabinets.

SEL Relay SEL-551 Series Overview:

Comprehensive Overcurrent Protection

The SEL-551 relay provides phase, negative sequence, zero sequence ground, and neutral overcurrent protection in a compact package, including a complete set of instantaneous, definite-time, and time-based overcurrent elements.

acSELerator QuickSet SEL-5030 Software

QuickSet allows you to develop relay settings, program SELogic control equations, and analyze post-fault event reports offline, helping to accelerate relay applications.

Protection and Control Logic

SELogic control equations with SELogic variables and timers allow for the use of traditional or advanced protection schemes. Programmable local control elements allow for front panel button control. Programmable text display dots provide enhanced local operator information.

Monitoring and Reporting

The SEL-551 relay features instantaneous, peak, and demand metering capabilities. Twenty 15-cycle oscilloscope data events and 512 Sequential Event Recorder (SER) records are stored in non-volatile memory.

Communication

A front-panel EIA-232 serial port, a rear-panel EIA-232/EIA-485 serial port, and ASCII, binary, and Modbus RTU protocols enhance integration capabilities.

SEL-551 Series Options:

Panel-mount or rack-mount hardware packages.

Connector packages include high-current interrupt output contacts.

Rear-mounted EIA-232 or EIA-485 serial communication port—either port includes demodulated IRIG-B timecode input.

A bracket with mounting holes for FT-1 switches (switch not included) for mounting a SEL-500 series relay in a 19-inch rack.

Conformal coatings: Protect equipment from harsh environments and air pollutants such as hydrogen sulfide, chlorine, salt, and moisture.

Our business scope includes:

Hydraulic components:

Solenoid directional valves, directional valves, check valves, stack valves, relief valves, counterbalancing valves, proportional valves, manual directional valves, flow valves, pressure reducing valves,

Throttle valves, pressure control valves, back pressure valves, filling valves, flow dividers, shuttle valves, pressure relays, cartridge valves, pneumatic valves, piston pumps,

Gear pumps, vane pumps, cycloidal hydraulic motors, oil coolers, hydraulic cylinders, etc.;

Pneumatic components:

Air source processor assemblies, filters, pressure regulating valves, oil feeders, solenoid valves, pneumatic valves, angle seat valves, manual valves, hand-operated valves, foot valves,

Mechanical valves, check valves, vacuum generators, cylinders, magnetic switches, shock absorbers, pressure gauges, quick couplings, floating couplings,

Pressure gauge switches, water coolers, electric positioners, PU tubing, vacuum suction cups, oil filters, vibrators;

Electrical components:

Relays, sensors, converters, proximity switches, encoders, programmable logic controllers (PLCs); Our company maintains a large inventory, with standard parts readily available. To better serve our customers across various industries, we also distribute other spare parts, utilizing professional sourcing channels to ensure reasonable prices.

Our products are widely used in industrial machinery, machine tools, plastics machinery, shoe machinery, brick machinery, metallurgy, mining, chemical industry, papermaking, coal mining, shipbuilding, power generation, construction machinery, environmental protection machinery, and many other fields.

Short delivery time, low prices, and our own customs clearance services. New and existing customers are welcome to inquire and purchase!