b6 
 
Introductio
-8 
MiCOM P40 Agile P442, P444 
 
 
3  PRODUCT SCOPE 
The MiCOM P442 and P444 Numerical Full Scheme Distance Relays provide 
comprehensive distance protection for different applications like: lines, cables, tapped lines, 
lines with multiple zero sequence sources, non-homogeneous lines, series compensated 
lines and parallel lines. 
The independently settable resistive reach for each zone allows easy application to short 
lines and cable protection. Using well-proven, patented techniques to directionalise, and 
making full use of digital memory, the relays can be applied in situations that can cause 
classic distance implementations to maloperate (crosscountry faults and close-up faults). 
The MiCOM P442 and P444 are in-built with a library of channel aided scheme logic, 
supplementary and back-up protection. It provides complete protection (4 alternative setting 
groups) to solidly earthed systems from distribution to transmission voltage levels. 
Three phase tripping with faulted phase indication is provided for all protection functions. In 
addition models P442 and P444 allow single-phase tripping for the distance protection and 
the channel aided DEF protection (67N). 
The P442 and P444 distance relays equipped with 150 MHz CPU and coprocessor board 
have been enhanced as described in the following table: 
Protection Functions Overview 
ANSI   IEC 61850 
Features  P442  P444 
21P  PDIS 
Quadrilateral full scheme phase distance (6 
zones) 
•  • 
21G  PDIS 
Quadrilateral full scheme ground distance (6 
zones) 
•  • 
    Load Blinder 
•  • 
50/51/67 
OcpPTOC
 / RDIR 
Directional / non-directional phase overcurrent (2 
stages) 
•  • 
50N / 51N 
/ 67N 
EfdPTOC / 
RDIR 
Directional / non-directional stand by earth fault (2 
stages) 
•  • 
67N  EfaPSCH 
Channel aided directional earth fault protection 
(DEF) 
•  • 
32N    Directional zero sequence power protection 
•  • 
67/46 
NgcPTOC 
/ RDIR 
Directional / non-directional negative sequence 
overcurrent 
•  • 
27  PTUV  Undervoltage (4 stages, 1
st
 stage DT and IDMT) 
•  • 
59  PTOV  Overvoltage (4 stages, 1
st
 stage DT and IDMT) 
•  • 
37    3-phase undercurrent (2 stages) 
•  • 
81U    Underfrequency (4 stages)  
•  • 
81O    Overfrequency (2 stages) 
•  • 
49  PTTR  Thermal overload protection 
•  • 
50 / 27  PSOF  Switch on to fault / trip on reclose (SOTF/TOR) 
•  • 
78 / 68  RPSB 
Power swing blocking & Out of step tripping 
(using PSL) 
•  • 
85  PSCH  Channel aided schemes (PUP, POP, Blocking) 
•  • 
    Weak Infeed (WI) Echo logic 
•  • 
   
Accelerated trip feature: Loss of Load - Zx 
extension 
•  • 
46BC    Broken conductor (open jumper) 
•  • 
50ST  OcpPTOC  Stub bus protection 
•  •