Siemens SIPROTEC 5 7SJ86 Overcurrent & Feeder Protection Relay

The Siemens SIPROTEC 5 7SJ86 is a modular numerical protection relay designed for reliable feeder and overcurrent protection in medium- and high-voltage power systems. Built on the advanced SIPROTEC 5 platform, it offers comprehensive protection, control, monitoring, and automation functions in a single device.

Engineered for modern digital substations, the relay supports IEC 61850 Edition 2 communication, enabling seamless integration with substation automation systems. Its modular hardware design allows flexible configuration of inputs and outputs, making it suitable for a wide range of applications.

The 7SJ86 provides dependable backup protection for line protection systems, ensuring fast and accurate fault detection, including phase faults and complex ground faults. With advanced fault detection methods and integrated fault locator functionality, it helps minimize downtime and improve operational reliability.

Additionally, the relay is configured using the powerful DIGSI 5 engineering tool, offering easy parameterization, monitoring, and system integration. Its robust cybersecurity features and high availability design make it ideal for critical infrastructure and industrial power networks.

Technical Specifications / Features

Protection Functions

• Overcurrent protection (phase & earth fault)
• Directional and non-directional protection
• Sensitive ground fault detection (harmonic, transient, admittance-based)
• Backup protection for line systems
• Arc fault detection (optional)
• Fault locator for accurate fault distance calculation

System & Application Features

• Suitable for feeder, line, and backup protection applications
• Supports all voltage levels (MV/HV systems)
• 3-pole tripping capability for fast fault isolation
• Designed for utility and industrial power networks

Hardware & Design

• Modular design with expandable I/O configuration
• Flexible inputs: approx. 11–23 binary inputs
• Flexible outputs: approx. 9–25 binary outputs
• Conformal coating for harsh environmental conditions
• High reliability and long service life

Communication & Integration

• Native IEC 61850 Edition 2 support (GOOSE, Sampled Values)
• Ethernet-based communication
• Supports protocols like Modbus TCP, PROFINET (via modules)
• Seamless integration into digital substations
• Compatible with the DIGSI 5 engineering tool

Cybersecurity

• Compliant with modern cybersecurity standards (NERC CIP / BDEW)
• Secure communication and firmware protection

Additional Features

• Integrated monitoring and control functions
• Power quality measurement capabilities
• Event and fault recording
• User-friendly configuration and operation