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MiCOM Agile P543, 544, 545 & 546

Line Differential Protection Systems

The MiCOM Agile P543, P544, P545 & P546 range of transmission-class protection relays provide comprehensive line protection for differential, subcycle distance and directional earth fault applications, 1/3 pole tripping. This range of products is ideal for HV, EHV and UHV applications on lines and cables of any length.

Key features:

  • Current transformer supervision operates with or without voltage inputs, to prevent any spurious tripping and raise the alarm

  • True subcycle distance protection with transmission class security and dependability 

  • Unparallelled speed, security and selectivity 

  • Compatible with 56/64kbps or 2Mbps for direct fiber or MUX communications channels

  • Suitable for use with equal or unequal transmit and receive path delays (eg SDH/SONET)

  • Full suite of monitoring, control and recording capabilities plus fault locator, autoreclose and check synchronism

  • Harsh environment coating as standard to all MiCOM relay to protect against corrosive gases such as H2S or SO2


The MiCOM Agile P543, P544, P545 & P546 range of transmission-class protection relays provide high speed current differential unit protection. They are designed for overhead line and cable applications, interfacing readily with the longitudinal (end-end) communications channel between line terminals. The interface options support direct fiber optic or multiplexed digital links.

Each of the models offer resident subcycle distance protection to complement the powerful suite of main and backup protection. Full scheme, five-zone distance protection is adopted from the class-leading MiCOMho MiCOM Agile P443. The product line becomes the standard in all HV, EHV and UHV line protection applications, duplicated where dual redundant main protection is demanded. Set any combination of differential, distance, overcurrent and reclosing, depending on the site needs. One universal relay type instead of two or more discrete models means reduced spares holding, less training, and lower cost. 

The MiCOM Agile P544 and P546 are suitable for the complex installation and feeders controlled by two circuit breakers such as breaker-and-a-half configurations with dual breaker autoreclose logic schemes with synchrocheck for both breakers.

Key benefits:

  • A universal relay that reduces spare holding - apply as a current differential relay, a distance relay, or both

  • Neutral differential boosts sensitivity of tripping for resistive earth faults, even for lines with heavy load-flow 

  • Transient biasing reduces CT knee point dimensioning by typically 25% compared to historical applications 

  • Differential protection adaptable to all different substation topologies: in-zone transformers and unequal line end CT ratios 

Main Characteristics: 

  • Comprehensive communication options including IEC 61850 Edition 1 and Edition 2

  • IEC 61850 redundant Ethernet, supporting self healing ring, RSTP, dual homing, PRP or HSR

  • Fast subcycle distance protection with 5 quadrilateral or mho zones and setting free power swing detection

  • InterMiCOM64 for transmitting 8 digital signals through teleprotection communication links




MiCOM Agile P54X Technical Guide

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