ALSTOM EP3-E-4-A Digital protection relay

ALSTOM EP3-E-4-A Technical Overview

1. General Description

The EP3-E-4-A is a digital protection relay designed for medium- to high-voltage electrical systems. It provides advanced protection, monitoring, and control for power distribution networks, industrial plants, and substations. Part of Alstom’s EP (Electrical Protection) series, this device ensures reliable fault detection and isolation to maintain grid stability and equipment safety.

2. Key Technical Specifications

• Electrical Ratings
  • Rated Voltage: 100–690V AC (phase-to-phase) or higher via voltage transformers (VT).
  • Current Inputs: 1A or 5A (configurable via CT secondary connections).
  • Frequency: 50/60 Hz (±5%).
  • Auxiliary Power Supply: 24–250V DC/AC (±20%, depending on variant).
• Protection Functions
  • Overcurrent Protection: Phase (51P) and earth fault (51N/G) with adjustable time-current curves (IEC/ANSI standards).
  • Short Circuit Protection: Instantaneous (50) and time-delayed (50TD) tripping.
  • Voltage Protection: Overvoltage (59), undervoltage (27), and voltage unbalance (47).
  • Frequency Protection: Over/under frequency (81O/U).
  • Additional Features: Directional protection (67), thermal overload (49), and harmonic restraint.
• Communication & Interfaces
  • Protocols: Modbus RTU/TCP, IEC 60870-5-103, or IEC 61850 (if supported).
  • Digital I/O: Programmable contacts for tripping, alarms, and automation logic.
  • Human-Machine Interface (HMI): LCD display with navigation buttons for local configuration.
• Environmental Ratings
  • Operating Temperature: -25°C to +70°C (-13°F to +158°F).
  • Humidity: 95% non-condensing.
  • Enclosure: IP40 (panel-mounted) or IP54 (dust/water-resistant variants).
• Mechanical Design
  • Dimensions: ~150mm x 180mm x 100mm (typical for DIN rail or panel mounting).
  • Weight: ~2–3 kg.
• Certifications
  • IEC 60255, IEEE C37.90, CE, and UL standards compliance.

3. Functional Capabilities

1. Adaptive Protection
   • Adjustable time-current curves (e.g., IDMTL, DT) to match network characteristics.
   • Logic programmable via proprietary software (e.g., MiCOM S1 Studio).
2. Fault Analysis & Logging
   • Event Recorder: Stores timestamps, fault currents/voltages, and trip signals.
   • Oscillographic Capture: Waveform recording for post-fault analysis.
3. Grid Interaction
   • Supports automatic reclosing (79) for temporary faults and synchronization (25).
   • Load shedding/restoration logic for power quality management.
4. Integration with SCADA/DMS
   • Real-time data sharing with control centers via communication protocols.
   • Remote configuration and firmware updates.
5. Self-Diagnostics
   • Continuous monitoring of hardware health (CT/VT circuits, power supply).

4. Typical Applications

• Substations: Protection of feeders, transformers, and busbars.
• Industrial Plants: Motor protection, generator backup, and distribution networks.
• Renewable Energy: Solar/wind farm grid connection protection.
• Railway Electrification: Overhead line (OHL) and traction power systems.

5. Ordering Information

• Model: EP3-E-4-A (suffixes may indicate voltage/communication options).
• Accessories: CT/VT modules, communication cables, mounting kits.

Key Advantages

• High Precision: 1% accuracy for current/voltage measurements.
• Flexibility: Modular firmware for future upgrades or function additions.
• Robustness: Designed for harsh environments (e.g., temperature extremes, EMI resistance).