P746/EN IT/G31 Introduction
(IT) 1-6
MiCOM P746
IT
3. PRODUCT SCOPE
The MiCOM P746 differential busbar protection relay has been designed for the protection of
a wide range of substation busbars from distribution to transmission voltage levels. The relay
includes a comprehensive range of non-protection features to aid with system diagnosis and
fault analysis. The P746 offers integral biased differential busbar, breaker failure, dead zone
and overcurrent protection and is suitable for application on solidly grounded systems. The
relay is especially suitable where a Centralised scheme solution is required.
The scheme can comprise:
• A single MiCOM P746 up to 6 sets of CTs
• Three MiCOM P746 for up to 18 (single phase) CTs per relay
• As many times “three MiCOM P746 for up to 18 (single phase)” when possible.
Which, with the MiCOM S1 V2 or MiCOM S1 Studio software and the Remote HMI
monitoring tool, allow full flexibility for all configurations up to 2 zones (or n times 2 zones).
3.1 Functional overview
The P746 Busbar protection contains a wide variety of protection functions.
The protection features are summarized below:
Protection Functions Overview
ANSI IEC 61850 P746
87BB / P PhsPDIF
Phase segregated biased current differential high speed
busbar protection
•
87CZ / P CzPPDIF
Check Zone segregated biased phase current differential
high speed busbar protection
•
50 / 51 / P OcpPTOC Phase overcurrent protection (2 stages)
•
50 / 51 / N EfmPTOC Earth overcurrent protection (2 stages)
•
50ST / P DzpPhsPTOC
Dead zone phase protection (short zone between CTs and
open CBs)
•
CTS Current transformer supervision (single box mode only)
•
VTS Voltage transformer supervision
•
50BF RBRF Breaker failure protection (LBB)
•
89 RBRF Lockout
•
ISL Isolator discrepancy alarm
•
OptGGIO Digital inputs
16 to 40
∗
RlyGGIO Output relays
16 to 32
∗
Front communication port (RS232)
•
Rear communication port (Kbus/EIA(RS)485)
•
Rear communication port (Ethernet) * Option
Time synchronisation port (IRIG-B) * Option
Redundant Ethernet Port Option
FnkGGIO Function keys 10
LedGGIO Programmable tri-colour LEDs 18
∗ Refer to the data sheet for model selection