Schneider Electric PowerLogic™ MiCOM P721 Numerical High Impedance Differential Relay

Schneider Electric PowerLogic™ MiCOM P721 Numerical High Impedance Differential Relay is designed for applications where fast and stable differential protection is required under heavy through-fault conditions. It forms part of the MiCOM P72x range and provides a straightforward high impedance protection solution for generator, reactor, motor and busbar protection schemes.

The MiCOM P721 is a **single-phase high impedance differential relay**. It is particularly suited for **restricted earth fault (REF)** and **balanced earth fault** protection where dependable operation and stability are both important. In these schemes, the relay works together with external stabilising components such as the MiCOM P79x resistor and metrosil unit to create a complete high impedance differential protection arrangement.

One of the practical advantages of the MiCOM P721 is that it keeps the simplicity of a traditional high impedance scheme while adding the benefits of a numerical relay. It offers event records, fault records, disturbance records and communication features that help operators and maintenance teams understand fault conditions more clearly and respond faster when a trip occurs.

Specifications

• Manufacturer: Schneider Electric
• Product Family: PowerLogic™ MiCOM
• Model: MiCOM P721
• Relay Type: Numerical High Impedance Differential Relay
• Protection Application: High Impedance Differential Protection
• Phase Configuration: Single-phase
• Main Use: Restricted Earth Fault (REF) and Balanced Earth Fault protection
• Suitable For: Generators, reactors, motors and busbar protection schemes
• Protection Principle: High impedance circulating current differential protection
• Technology: Numerical / Digital relay
• Records Available: Event records, fault records and disturbance records
• Communication Features: Available as part of numerical relay functionality
• Accessory Compatibility: Designed for use with MiCOM P79x resistor and metrosil unit in high impedance schemes

Features

• Single-phase high impedance differential protection relay.
• Suitable for restricted earth fault and balanced earth fault applications.
• Designed for schemes that require stability during heavy through faults.
• Helps deliver fast fault clearance for internal faults within the protected zone.
• Combines the simplicity of traditional high impedance protection with numerical relay benefits.
• Supports event recording, fault recording and disturbance recording.
• Works with MiCOM P79x resistor and metrosil unit for complete high impedance differential protection schemes.
• Suitable for generator, motor, reactor and busbar protection applications.

Applications

• Restricted Earth Fault (REF) protection
• Balanced Earth Fault protection
• Generator differential protection schemes
• Reactor protection schemes
• Motor protection schemes
• Busbar protection schemes
• Utility and industrial protection panels
• High impedance differential protection systems

Schneider Electric PowerLogic™ MiCOM P721 Numerical High Impedance Differential Relay is a practical choice for high impedance differential schemes where stable operation, fast internal fault clearance and dependable earth fault protection are required.