Distance protection for transmission lines

The SIPROTEC 7SA522 incorporates several protective functions usually required for transmission line protection.

• High-speed tripping time
• Suitable for cables and overhead lines with or without series capacitor compensation
• Self-setting power swing detection for power swing frequencies up to 7 Hz

Digital relay-to-relay communication for two and three terminal topologies

• Adaptive auto-reclosure (ADT)

Hardware

• Binary inputs: 8 to 24

• Binary outputs : 16 to 44
• High-speed trip outputs: 5/10 (optional)
• Text display
• Surface-mounting or flush-mounting housing

Communication interfaces

• System port 
  – IEC 61850

  – IEC 60870-5-103 
  – PROFIBUS DP
  – DNP 3 

• Service port
  – DIGSI 4
  – Modem
  
• 2 serial protection data interface for teleprotection
• Front port
  – DIGSI 4
• Time synchronization via IRIG B, DCF 77 or system interface

Protection functions

• Non-switched distance protection with 6 measuring systems (21/21N)

• High resistance ground (earth)-fault protection for single and three-phase tripping (50N, 51N, 67N)

• Tele (pilot) protection (85)

• Fault locator (FL)

• Power swing detection / tripping (68/68T)

• Phase-overcurrent protection (50/51)

• STUB bus overcurrent protection (50STUB)

• Switch-onto-fault protection (50HS)

• Over/undervoltage protection (59/27)

• Over/underfrequency protection (81O/U)

• Auto-reclosure (79)

• Synchro-check (25)

• Breaker failure protection (50BF)

Control functions

• Commands for control of CB and isolators

Monitoring functions

• Trip circuit supervision (74TC)

• Self-supervision of the relay

• Measured-value supervision

• Event logging/fault logging

• Oscillographic fault recording

• Switching statistics

Front design

• User-friendly local operation with numeric keys

• LEDs for local alarm

• PC front port for convenient relay setting

• Function keys