Product Overview

• Part No: MBCI01N1AB0761B
• Brand: ALSTOM

• Category: Pilot Wire Current Differential Protection RelayMBCI01N1AB0761B belongs to ALSTOM classic MBCI series static circulating current differential relay (Translay type). Based on circulating current differential principle, it is designed for unit protection of transmission lines and cable feeders. The relay compares currents at both line terminals, providing fast tripping for internal faults and high stability against external through faults. It is adaptable to a certain range of pilot wire loop resistance and equipped with mechanical operation flag indicator. With standard plug-in housing, it is a common spare part for high voltage feeder protection panels in power plants and substations.

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Core Features

• Circulating current differential principle, high stability for external through faults
• Fast tripping response for internal phase and earth faults on feeders and cables
• Adjustable operating current setting to match field CT configuration
• Mechanical trip flag indicator for visible fault record
• Standard plug-in modular construction for rapid on-site replacement
• Built-in surge suppression, strong anti-interference performance for substation environment

• Passed EMC, vibration and thermal cycling long-term reliability testing

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Technical Specifications

• Auxiliary Supply: 110V/220V AC/DC
• Rated CT Input: 1A / 5A
• Operating Frequency: 50/60Hz
• Operating Temperature: -20°C ~ +60°C
• Storage Temperature: -40°C ~ +85°C
• Installation: Chassis plug-in mounting

• Front Protection Class: IP40

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Compatibility & Application

• Compatible with ALSTOM legacy secondary protection cabinet systems
• Widely applied in thermal power plants, captive power stations and distribution substations
• Used for unit protection of overhead transmission lines, underground cables and bus tie feeders