Siemens SIPROTEC 5 7UM85 Generator Protection Relay

The Siemens SIPROTEC 5 7UM85 is a high-performance, modular numerical relay designed to provide comprehensive protection for generators and power plant units. Built on the advanced SIPROTEC 5 platform, it integrates protection, control, monitoring, and automation functions into a single flexible device.

Engineered for modern power systems, the 7UM85 ensures safe and reliable operation of generators across a wide range of applications—from small industrial generators to large utility power plants. Its modular hardware architecture allows flexible configuration of inputs and outputs, making it adaptable to different system requirements.

The relay supports advanced protection functions such as differential protection, stator and rotor earth fault protection, and short-circuit protection. It also enables accurate fault detection and fast tripping to minimize equipment damage and downtime.

With seamless integration into digital substations, the 7UM85 supports IEC 61850 communication and is engineered using the powerful DIGSI 5 software tool. Its robust design, cybersecurity features, and high availability make it suitable for critical infrastructure and demanding environments.

Technical Specifications / Features

Protection Functions

• Generator differential protection
• Short-circuit protection (overcurrent & impedance-based)
• Stator earth fault protection (90% / 100% with advanced methods)
• Rotor earth fault protection
• Underexcitation and overexcitation protection
• Reverse power protection (SIL2 certified)
• Protection for synchronous motors (optional use)

System & Application Features

• Designed for generators and power plant units
• Suitable for unit and busbar-connected generator schemes
• Can also provide combined generator-transformer protection
• Ensures reliable operation in utility and industrial environments

Hardware & Design

• Modular SIPROTEC 5 design with expandable I/O
• Supports up to:
  • 16 current transformers
  • 8 voltage transformers
  • 7–15 binary inputs
  • 9–20 binary outputs
• Conformal coating for harsh environments
• Available with ATEX certification for explosive areas

Communication & Integration

• IEC 61850 compliant (digital substation ready)
• Supports Ethernet-based communication
• Seamless integration with the DIGSI 5 engineering tool
• Flexible system integration with multiple I/O configurations

Cybersecurity & Reliability

• SIL2-certified functions (e.g., reverse power protection)
• Secure firmware and communication architecture
• Designed for high availability and critical infrastructure

Additional Features

• Advanced measurement and monitoring capabilities
• Power quality and disturbance recording
• Event and fault recording for analysis
• Easy configuration and operation via DIGSI 5