Schweitzer Engineering Laboratories (SEL) produces a wide range of relays for protection, automation, and control in power systems.
IEDs (Intelligent Electronic Devices) from SEL are digital relays that provide protection, monitoring, automation, and communication for electrical power systems. They protect assets like generators, transformers, transmission lines, motors, and feeders.
Key Features of SEL Relays
- Protection: Overcurrent, distance, differential, voltage, frequency, and specialized schemes.
- Automation: Logic, sequence of events, programmable automation controller functions.
- Communications: IEC 61850, DNP3, Modbus, synchrophasors, SEL proprietary protocols.
- Cybersecurity: Role-based access control, encrypted communications.
- Reliability: Built for harsh environments, long life, and easy firmware upgrades.
Here are examples of Common SEL IEDs
- SEL-351: Feeder protection.
- SEL-487E: Transformer differential protection.
- SEL-421: Line protection, including distance and pilot schemes.
- SEL-751: Overcurrent and feeder protection.
- SEL-751A: Motor protection.
- SEL-700G: Generator protection.
- SEL-311C: Transmission line protection.
Training content
Introduction to SEL IEDs
- What is an IED?
- Role of SEL in power system protection.
- SEL design philosophy (simplicity, reliability, cybersecurity).
- Comparison with other manufacturers (Siemens SIPROTEC, GE, ABB).
Core Functions of SEL Relays
- Protection: Overcurrent, distance, differential, voltage/frequency.
- Automation: Logic, control, event recording.
- Monitoring: Power quality, synchrophasors (PMU).
- Communication: IEC 61850, DNP3, Modbus, MIRRORED BITS®.
Hardware and Architecture
- Relay construction & hardware modules.
- Inputs/outputs (CT, VT, digital I/O).
- Human-Machine Interface (HMI).
- Power supply and redundancy.
Software Tools for SEL IEDs
- AcSELerator QuickSet® – settings and configuration.
- Event analysis tools.
- Communications setup (protocols, SCADA integration).
Key SEL Relays & Applications
- SEL-351: Feeder protection.
- SEL-487E: Transformer differential.
- SEL-421: Transmission line (distance protection).
- SEL-700G: Generator protection.
- SEL-751: Motor and feeder protection.
Protection Schemes Using SEL Relays
- Overcurrent coordination.
- Transformer differential with backup.
- Line protection: distance, pilot, permissive schemes.
- Generator protection schemes.
- Motor start-up and overload protection.
Advanced Topics
- IEC 61850 applications: GOOSE messaging, MMS.
- Synchrophasors & Wide-Area Monitoring (WAM).
- Cybersecurity features: RBAC, secure communications.
- Automation logic (SELogic control equations).