Line distance protection relay Siemens Power Transmission Distribution

The SIPROTEC 4 7SA522 is a distance protection relay for transmission lines. This relay provides full-scheme distance protection and incorporates all functions usually required for the protection of a power line. The relay is designed to provide fast and selective fault clearance on transmission and subtransmission cables and overhead lines with or without series capacitor compensation. The power system star point can be solid or resistance grounded (earthed), resonant-earthed via Peterson coil or isolated. The 7SA522 is suitable for single-pole and three-pole tripping applications with and without tele (pilot) protection schemes.

The 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 frequencies up to 7 Hz
• Digital relay-to-relay communication for two and three terminal topologies
• Adaptive auto-reclosure (ADT)

One of the communication interfaces is system interface for connecting to a control system via IEC 61850 Ethernet protocol.

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