Siemens SIPROTEC Compact 7SD80 Line Differential Protection Relay

The Siemens SIPROTEC Compact 7SD80 is a compact and reliable line differential protection relay designed for protecting overhead lines and cable feeders in medium- and high-voltage power systems. As part of the SIPROTEC Compact series, it provides high-speed and selective fault clearance in a space-saving and cost-effective design.

The relay uses the current differential protection principle, comparing currents at both ends of a line to detect internal faults with high accuracy. It ensures fast tripping for internal faults while maintaining stability during external faults and through-load conditions.

With its predefined hardware configuration, the 7SD80 offers easy installation, simplified commissioning, and reduced engineering effort, making it suitable for standard line protection applications. It supports modern communication protocols and integrates seamlessly into digital substations.

Main Function

• Line Differential Protection

Tripping

• 3-pole tripping
• Ultra-fast fault clearance for internal faults

Technical Specifications

Protection & Functional Features

• Line differential protection based on:
  • Current comparison between line ends
• Detects:
  • Phase faults
  • Earth faults
• High-speed tripping for:
  • Internal faults
• Stable operation for:
  • External faults
  • Load conditions
• Includes:
  • Backup overcurrent protection
• Ensures:
  • Selective and reliable fault isolation

Hardware & Compact Design

• Compact, fixed hardware design (non-modular)
• Predefined configuration for standard applications
• Typical configuration:
  • CT inputs: 4
  • VT inputs: 4
  • Binary inputs: ~11
  • Binary outputs: ~9
• Space-saving and cost-effective solution

Communication & Protocols

• Line differential communication via:
  • Fiber optic channels
• IEC 61850 compliant
• GOOSE messaging support
• Supports:
  • Modbus TCP
• Enables integration into digital substations

Engineering & Software

• Configurable via DIGSI 5
• Simplified parameterization and commissioning
• Predefined templates for line protection

Advanced Features

• High-speed differential protection
• Reliable operation using SIPROTEC platform
• Basic disturbance recording and monitoring
• Secure communication between line ends

Applications

• Protection of:
  • Overhead transmission lines
  • Underground cables
• Medium- and high-voltage networks
• Utility substations
• Industrial power systems