Major Features and Benefits:-

The SEL-311C Transmission Protection System is an advanced, full-featured, three-pole trip, three-pole reclose relay for transmission protection applications.

Protection Functions

➤ Four zones of mho phase-distance elements, and four zones of mho and quadrilateral ground-distance elements provide comprehensive distance protection for transmission lines.

➤ Settings allow three-phase wye or three-phase delta voltage inputs.

➤ Coupling capacitor voltage transformer (CCVT) transient overreach logic enhances the security of Zone 1 elements.

➤ Out-of-step logic blocks distance elements for stable power swings or trips for unstable power swings. ➤ Additional resistance blinders unblock distance elements if a three-phase fault occurs during a swing.

➤ Negative-sequence directional overcurrent elements unblock distance elements if an unbalanced fault occurs during a power swing.

➤ Load-encroachment logic distinguishes between heavy load and three-phase faults.

➤ Built-in communications-assisted trip scheme logic permits fast trip times, reducing fault duration that adversely impacts system stability.

➤ Phase, negative-sequence, and residual-ground overcurrent elements with directional control optimize network protection for lines and equipment.

➤ Best Choice Ground Directional Element® logic optimizes directional element performance and requires no directional settings.

➤ High-speed breaker failure element and native breaker failure logic enhance breaker failure detection.

➤ Implement load shedding and other control schemes with over-/underfrequency and over-/undervoltage elements and powerful SELOGIC® control equations.

➤ SELOGIC control equations permit custom programming for traditional and unique protection, automation, and control functions.


Automatic Reclosing and Synchronism Check

➤ Program as many as four shots of automatic reclosing.

➤ Supervise manual or automatic reclosing with synchronism check and voltage condition logic.



➤ Improve operator awareness of system conditions with standard IEEE C37.118-2005 Level 1 synchrophasors at as many as 60 messages per second.

➤ Synchronize 128 sample-per-cycle oscillography and event reports to the microsecond to reconstruct complex disturbances. Synchronize meter reports to verify proper phasing.

➤ Use the “MRI of the power system” to replace state estimation with state measurement.



➤ Improve maintenance scheduling by using circuit breaker contact wear monitor and substation battery voltage monitors.

➤ Use alarm elements to inhibit reclosing and provide local and remote alarm indication.

➤ Analyze oscillographic and Sequential Events Recorder (SER) reports for rapid commissioning, testing, and post-fault diagnostics.

➤ Use unsolicited SER protocol to allow station-wide collection of binary SER messages with original time stamp for easy chronological analysis.

➤ Synchronize all reports with IRIG-B on the standard rear-panel BNC or on Serial Port 2, from Simple Network Time Protocol (SNTP) on the standard or optional Ethernet connections, or via DNP serial or Ethernet protocols. Connect all possible time sources and the relay automatically selects the best.


Fault Locator

➤ Efficiently dispatch line crews to quickly isolate line problems and restore service faster.

➤ Ensure proper distance element operation with fault resistance calculations for phase and ground faults.


Operator Interface and Controls

➤ Standard target LEDs annunciate trip and status indication and fault type.

➤ Ten optional programmable operator pushbuttons and indicating LEDs with configurable labels eliminate expensive panel-mounted control switches, lights, and associated wiring.

➤ Optional programmable target LEDs increase the flexibility of annunciating trip and status indication.

➤ Two-line rotating LCD display provides added operator information with programmable display points. ➤ Optional SafeLock® trip/close pushbuttons with high-visibility breaker status LEDs eliminate expensive breaker control switches and position indicating lights. The breaker status LED clusters are bright and easy to see from all viewing angles. Schweitzer Engineering Laboratories, Inc. SEL-311C-1 Data Sheet 3

Communications Protocols

➤ Optional IEC 61850 MMS and GOOSE. As many as seven MMS sessions, guaranteed GOOSE performance with 24 subscriptions and eight publications.

➤ Standard Modbus with label-based map settings (serial and Ethernet—as many as three sessions).

➤ Standard DNP3 Level 2 with label-based map settings (serial and Ethernet—as many as six sessions).

➤ IEEE C37.118-2005 Synchrophasor Protocol (serial and Ethernet).

➤ ASCII, SEL Fast Meter, SEL Fast Message, SEL Unsolicited SER, SEL Fast Operate, and SEL Distributed Port Switch (LMD) serial protocols are all standard.

➤ Standard Telnet and integrated web server on Ethernet.

➤ Standard dual-channel MIRRORED BITS® communications.

➤ Parallel redundancy protocol (when supported by hardware).


Communications Hardware

Two 10/100BASE-T Ethernet ports with RJ45 connector included.

➤ One or two 10/100BASE-FX Ethernet ports with LC multimode fiber-optic connectors optional.

➤ One 10/100BASE-T Ethernet port and one 10/100BASE-FX Ethernet port with LC multimode fiberoptic connectors optional.

➤ Front-panel high-speed USB Type-B port included.

➤ Front-panel EIA-232 DB-9 serial port included.

➤ Two rear-panel EIA-232 DB-9 ports included.

➤ One optional rear-panel EIA-485 port with five-position compression terminal block.

➤ One optional SEL-2812-compatible fiber-optic serial port.


Other Features and Options

➤ Nominal 1 A or 5 A current inputs.

➤ Available 750 KB of on-board storage space for ACSELERATOR QuickSet® SEL-5030 Software settings file, QuickSet Design Template, or anything else you choose.

➤ Expanded I/O is available in the 3U chassis. Order any one of the following I/O options:

➣ Option X: No extra I/O board

➣ Option 2: Additional 8 Inputs and 12 Standard Outputs

➣ Option 4: Additional 16 Inputs and 4 Standard Outputs

➣ Option 5: Additional 8 Inputs and 8 High-Speed, High Interrupting Current Outputs

➣ Option 6: Additional 8 Inputs and 12 High Interrupting Current Outputs


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