SEL – 411L Advanced Line Differential Protection, Automation, and Control System

Apply the SEL-411L for complete protection and control of any transmission line (short, long, or series-compensated). The SEL-411L provides differential and distance protection with both phase- and sequence-based operating elements for sensitivity and high-speed operation.



You can choose from many popular fiber and multiplexed communications options. Distance protection and logic from a complete SEL-421 Protection, Automation, and Control System are included to provide redundant protection and integration. The SEL-411L includes a traveling-wave fault locating method to locate faults within a tower span. Broken conductor detection in the SEL-411L detects conductor breaks in overhead lines. This function can prevent a shunt fault that could occur from a falling conductor. Transform the way you modernize your substation with optional Time-Domain Link (TiDL) technology or Sampled Values (SV)-based technology using IEC 61850-9-2.



Line Current Differential Protection—Apply subcycle single or three pole line current differential protection with backup distance protection for transmission lines using serial or Ethernet for differential communications. Patented generalized Alpha Plane technology combined with overcurrent supervision, external fault detection, and disturbance detection logic enables the 87L function to operate with exceptional security and sensitivity. You can invert individual or grouped CT or PT polarities to account for field wiring or protection zone changes.

Series-Compensated and Long Lines—Prevent Zone 1 overreach on series-compensated lines with optional logic in the SEL-411L-1. Built-in charging compensation improves the sensitivity and speed of differential protection for long lines.

In-Line Transformers—Simplify protection schemes and reduce equipment costs by providing complete protection for the combined line and transformer. The 87L function of the relay allows in-line transformer applications that compensate for vector group, ratio, and zero sequence of the in-zone transformer. Use harmonic blocking, restraint, or both for stabilization under magnetizing inrush conditions.

Out-of-Step Blocking and Tripping—During power swings, the relay automatically selects either out-of-step blocking or out-of-step tripping. Out-of-step blocking enhances your security by blocking distance elements during stable swing conditions. During unstable power swing conditions, the SEL-411L implements out-of-step tripping to maintain balance between generation and load.

Multiterminal Transmission Lines—Protect lines with up to four terminals. Apply the SEL-411L on breaker-and-a-half bus configurations or other two-breaker schemes with the relay’s dual CT and PT inputs. Efficiently dispatch line crews to quickly isolate line problems and restore service faster. The multiterminal fault location system quickly locates faults, even on lateral transmission lines.

Flexible Communications Options—Use small form-factor pluggable (SFP) transceivers on designated process bus, station bus, and engineering access ports in the five-port Ethernet card. Choose between single- and multimode communications options for increased flexibility. All ports support 100 Mbps SFP transceivers, and process bus ports also support 1 Gbps SFP transceivers.ase machine life by detecting faults and abnormal conditions before they cause permanent damage. The 18 current and 6 voltage inputs on the SEL-400G enable complex generator protection schemes or protection of other equipment, such as transformers.

Traveling-Wave Fault Locator—Accurately pinpoint faults with time-synchronized traveling-wave fault location. Save time and money by sending maintenance crews to the tower nearest the fault.

Broken Conductor Detection—Detect conductor breaks in subtransmission or transmission overhead lines using the broken conductor detection function. This function can prevent a shunt fault that could occur from a fallen conductor. Configure the broken conductor detection function to block autoreclose attempts onto permanent faults. The function also provides the location of the conductor break to aid in restoring the power line.

Bay Control, Reclosing, and Breaker Failure Detection—Apply complete bay control, reclosing, and breaker failure protection for two breakers. Monitor circuit breaker performance, including the average and last tripping time, motor run time, and contact-interrupting duty.

Reliable Distance Protection—Provide reliable backup protection with five zones of phase and ground distance elements that include directional overcurrent elements for subcycle operation and security.

Thermal Overload Protection—Use the three independent IEC 60255-149 thermal elements to activate a control action, issue an alarm, or trip when equipment overheats as a result of adverse operating conditions. The SEL-2600 RTD Module provides ambient temperature measurements.

Digital Secondary System Technologies—SEL TiDL and SV-based solutions replace copper with fiber to increase safety, improve reliability, and limit the impact of an electromagnetic pulse. Apply the SEL-411L-2 TiDL relay with the SEL-TMU TiDL Merging Unit in the field to provide remote I/O and digitize analog signals. This simple point-to-point solution with a strong cybersecurity posture is easy to implement. Apply the IEC 61850-compliant SEL-411L-2 SV relay to receive SV data from a remote merging unit via a network. Improve system availability in SV applications with the Parallel Redundancy Protocol (PRP) or seamless failover using a five-port Ethernet card.

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