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Line Protection

Home > Grid Automation > Protection Relays > Line Protection > P441, P442 & P444

Related Links
  Interactive Selector Guide - Line Differential
  Interactive Selector Guide - Line Distance
  Spotlight Application
  Typical Applications
  Transmission Principles & Protection
  GSA Schedule
  Legacy Transmission Protection

MiCOM Agile P441, P442 & P444
Distance Protection Relays

Part of the MiCOM P40 platform, the Agile P441, P442 and P444 numerical full scheme distance relays provide flexible, fast and reliable protection of transmission and sub-transmission lines. They include full scheme 6-zone distance, plus aided directional earth fault (DEF) and comprehensive backup protection for utility lines and cables at all voltage levels, particularly oriented towards transmission grids.

These distance protection systems are ideal for single circuit breaker application, single and/or 3-pole tripping, and includes a full suite of monitoring, control and recording capabilities plus fault locator, autoreclose and check synchronism.

Key features:

  • Dual algorithm distance operation for maximum fault detection dependability
  • Deploy in traditional CT/VT applications, or digital substation architectures with merging units and non-conventional instrument transformers using IEC 61850-9-2 process bus
  • Distance to fault location assists dispatching of maintenance crews 
  • Full-scheme relay offers fast, discriminative response to double-circuit, cross-country and evolving faults
  • No internal batteries in GE-branded models – removes a maintenance item and eases air-freight logistics
  • NERC CIP cybersecurity including role-based access control (RBAC), RADIUS and SysLog
  • Advanced binary inputs comply with the harshest norms for surge withstand, plus the ESI 48-4 EB2 standard. Spurious wiring pickup is eliminated without the use of interposing relays, external resistors or time delays. Battery/wiring faults, switching noise, and induction from long parallel circuits are tolerated without misoperation
What's New

What's New

MiCOM P40 Agile Explorer

Enhanced Ethernet board module with switchable Ethernet redundancy delivered in a single model. The new board module is supported on P442 and P444, also delivered along with the NERC CIP v6 Cybersecurity release, software 91.
It supports PRP, HSR and RSTP in one model, allowing a single P40 model to be used in any application requiring redundant Ethernet communications.
The new module is designed to handle high density traffic in the IEC 61850-8-1 network, with time latency halved. Larger architecture digital substations can also be supported, with up to 50 nodes now possible in IEC 62439 HSR rings.

Key Features & Benefits:

  • Universal IRIG-B – Modulated and demodulated supported in the same model
  • HSR Ring – Extended to 50 node support for larger substation architectures
  • Fast performance, particularly in onerous applications such as where process bus GOOSE is used for tripping purposes
  • NERC CIP cybersecurity including role-based access control (RBAC), RADIUS and SysLog


The Agile P441, P442 and P444 have a settable quadrilateral operating characteristic that offers consistent 0.85-1.1 cycle zone 1 operating time for general distance application. Customers have a choice of cost-effective built-in teleprotection with InterMiCOM, to implement permissive, blocking and intertripping schemes.
The IEC 61850 redundant Ethernet option offers RSTP and IEC 62439 PRP/HSR – with the HSR support extending for up to 50 nodes in a station bus ring.

Key benefits:

  • Comprehensive communication options including IEC 61850 and redundant Ethernet ports
  • IEC61850-9-2 interface option allows integration within digital substation process bus architectures
  • Unparallelled speed, security and selectivity
  • User customisable with graphical tools

Functional Block Diagram

Functional block diagram

ANSI ® Device Numbers and Functions

Device Number Function
25 Check Synchronising
27 Phase and Line Undervoltage
37 Undercurrent
46 Negative Sequence Overcurrent
49 Thermal Overload
50 Phase Definitive Time Overcurrent
51 Phase Inverse-Time Overcurrent
52 Circuit Breaker Control
59 Phase and Line Overvoltage
67 Directional Phase Overcurrent
68 Power Swing Blocking
Device Number Function
79 Autoreclose
85 InterMiCOM Teleprotection
86 Latching/Lockout Contacts
21BL Load Encroachment/Blinder
21FL Fault Locator
21FG Ground Distance
21P Phase Distance
32N Directional Zero-Sequence Power
46BC Broken Conductor
50/27 Switch-on to Fault
50BF CB Failure
Device Number Function
50N Earth Fault Definite Time Overcurrent
50ST Stub Bus Protection
51FF VT Fail Overcurrent
51N Neutral/Ground IDMT Overcurrent
67N Directional Neutral/Ground Overcurrent
81O Overfrequency
81U Underfrequency
CTS CT Supervision
CVTS Capacitor VT Supervision
TCS Trip Circuit Supervision
VTS VT Supervision


P441 Line-Distance Management IED. P441 is under last-time buy. Orders may be placed until  30th June 2024 and will be fulfilled based upon availability. As an alternative, please refer to P44 or P444.

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P442 Line-Distance Management IED
The P442 is under last-time buy. Orders may be placed until 15th June 2025 and will be fulfilled based upon availability. As an alternative, please refer to P44 or P444.

Buy Now

P444 Line-Distance Management IED for Transmission

Buy Now

MiCOM S1 Agile

Key benefits:

Engineering Tool Suite

S1 Agile is the truly universal PC tool for MiCOM Agile relay, assemble all tools in a palette for simple entry, with intuitive navigation via fewer mouse-clicks. No-longer are separate tools required for redundant Ethernet configuration, phasor measurement unit commissioning, busbar scheme operational dashboards, programmable curve profiles or automatic disturbance record extraction – applications are embedded. MiCOM S1 Agile supports all existing MiCOM, K-Series and Modulex, including a utility for automatic conversion of setting files from previous generations of numerical relays like K-series and MiCOM P20 to the latest P40 Agile models.

To move to the future, with no loss of functionality, no loss of device support, and full compatibility with your installed base and system architecture – request a copy of S1 Agile with the contact form link below.

MiCOM S1 Agile software

Key features in the MiCOM S1 family:

MiCOM S1 Agile software request

To receive the MiCOM S1 Agile, please use our Contact form. This will also ensure that you are kept up-to-date with the latest enhancements, including updates and bug fixes.

Refurbishment Solutions – “If It’s Blue Think to Renew”

GE’s latest MiCOM P440 series models P441 to P444 inclusive offer an ideal path to refurbish an older installed base of MiCOM P440 relays. Whether those older products were initially sold as Alstom or AREVA-branded products, newer models retain pin-pin refurbishment capability. Advantageously, users can benefit from the advancements made in protection, control, communications, hardware and cybersecurity that have taken place in the intervening years. The new P40 retains form, fit and function compatibility but delivers the latest platform and software ready for today’s environment, and for future-proofed application for the decades ahead.

Pin-Pin Upgrade Methodology: