1. Product Overview

Key Features

• Compliant with the international standard IEC 60947-2
• Self-powered design with CT power supply, ensuring stable operation of all protection functions under all working conditions
• Integrated with comprehensive functions including protection, measurement, monitoring, signal output, testing, control, communication and data storage

2. Technical Parameters

2.1 Electrical Characteristics

2.2 Protection Function Configuration

• Overload protection (L function, non-disablable)
• Short-circuit protection (G/S function)
• Under-voltage / Over-voltage protection
• Earth fault protection
• Reverse active power protection
• Phase unbalance protection
• Inverse time overcurrent protection

3. Product Advantages & Features

3.1 Core Advantages

• Self-powered Design: Draws operating energy from current transformers (CTs) to guarantee reliable operation of all protection functions under any fault condition.
• Thermal Memory Function: Effectively isolates faulty areas to ensure continuous and stable operation of the overall power system.
• Graphical User Interface: Equipped with an LCD display and membrane keyboard for intuitive parameter configuration and real-time status monitoring.

3.2 Extended Functions

• Voltage & Power Measurement: Supports real-time monitoring of key electrical operating parameters.
• Powerful Communication Capability: Built-in RS485 bus with Modbus protocol support, enabling seamless connection and data interaction with SCADA systems.
• Selective Protection: Supports Zone Selective Interlocking (ZSI) function for precise fault isolation.
• Programmable Output: Provides P1/P2 programmable electrical signal output ports for flexible system matching.

3.3 Safety Characteristics

• Overload Protection (L Function): The only non-disablable core protection function, dedicated to protecting the unit and circuit equipment from overload damage.
• Earth Fault Protection: Realized through MS/NS transformer grounding wire to prevent electric leakage and earth fault risks.
• Self-diagnosis Function: Supports automatic operational testing and real-time fault diagnosis to improve system stability and maintainability.

4. Structure & Composition

4.1 Display & Control Module

• Graphical LCD display screen
• Membrane control keyboard
• LED status indicator lights

4.2 Protection Processing Unit

• Digital signal processor (DSP)
• Memory module (for historical data recording and parameter storage)
• Professional protection algorithm module

4.3 Input / Output Interface Module

• K51/μP: Microprocessor electrical alarm signal interface
• K51/1-8: Signal unit output interfaces
• K51/GZin/GZout: Zone selective input and output interfaces
• K51/SZin/SZout: Selective protection input and output interfaces
• K51/Y0/YC: Trip control coil interface

4.4 Communication Module

• Standard RS485 communication interface
• Built-in Modbus protocol support
• Optional LON communication module for extended networking

5. Application Fields

• Industrial Sector: Factory power distribution systems, production line electrical protection
• Commercial Buildings: Power distribution systems of large shopping malls and office buildings
• Infrastructure: Data centers, hospitals, transportation hubs and other key public facilities
• Energy Industry: Substations, auxiliary equipment of power plants

6. Installation & Maintenance Guidelines

6.1 Wiring Requirements

• Shielded twisted-pair cables shall be adopted for all input and output circuits, with a maximum cable length of 300 meters.
• The maximum length of shielded wires between the voltage converter and the circuit breaker is 15 meters.
• The trigger coil power supply is prohibited to be directly taken from the main circuit.

6.2 Installation Precautions

• Only accessories specified in the ABB SACE order confirmation shall be matched with the circuit breaker.
• For 3-pole circuit breakers, short-circuit treatment of T3/T4 poles shall be implemented in accordance with official instructions.
• Short-circuit connection shall be made to the T/N terminals of the converter for external neutral extension.
• A 30ms automatic start delay shall be reserved for the low-voltage trigger.

6.3 Connection & Configuration Specifications

• RS485 bus connection shall comply with the specifications of document RH0297 (LON) and RH0298 (MODBUS).
• The installation and configuration of 4-pole circuit breakers shall strictly follow the dedicated configuration requirements.