Areva MiCOM P441, Technical Manual

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P44x/EN AP/E33 Application Notes
Page 8/220 MiCOM P441/P442 & P444
1.2.1 Protection Features
The distance relays offer a comprehensive range of protection functions, for application to
many overhead line and underground cable circuits. There are 3 separate models available,
the P441, P442 and P444. The P442 and P444 models can provide single and three pole
tripping. The P441 model provides three pole tripping only. The protection features of each
model are summarised below:
•
21G/21P : Phase and earth fault distance protection, each with up to 5 independent
zones of protection. Standard and customised signalling schemes are available to
give fast fault clearance for the whole of the protected line or cable.
•
50/51 : Instantaneous and time delayed overcurrent protection - Four elements are
available, with independent directional control for the 1
st
and 2
nd
element. The fourth
element can be configured for stub bus protection in 1½ circuit breaker arrangements.
The 3
rd
element can be used for SOFT/TOR logic.
•
50N/51N : Instantaneous and time delayed neutral overcurrent protection. Two
element are available and four threshold from next version C1.0 (model 020G or
020H).
•
67N : Directional earth fault protection (DEF) - This can be configured for channel
aided protection, plus two elements are available for backup DEF.
•
32N : Maximum of Residual Power Protection - Zero sequence Power Protection
This element can provide protection element for high resistance fault, eliminated
without communication channel.
•
27 : Undervoltage Protection - Two stage, configurable to measure either phase to
phase or phase to neutral voltage. Stage 1 may be selected as either IDMT or DT and
stage 2 is DT only.
•
59 : Overvoltage Protection - Two stage, configurable to measure either phase to
phase or phase to neutral voltage. Stage 1 may be selected as either IDMT or DT and
stage 2 is DT only.
•
67/46 : Directional or non-directional negative sequence overcurrent protection - This
element can provide backup protection for many unbalanced fault conditions.
•
50/27 : Switch on to fault (SOTF) protection - These settings enhance the protection
applied for manual circuit breaker closure.
•
50/27 :Trip on reclose (TOR) protection - These settings enhance the protection
applied on autoreclosure of the circuit breaker.
•
78 : Power swing blocking - Selective blocking of distance protection zones ensures
stability during the power swings experienced on sub-transmission and transmission
systems. From version C1.0, the relay can differentiate between a stable power swing
and a loss of synchronism (out of steps).
•
VTS : Voltage transformer supervision (VTS). To detect VT fuse failures. This
prevents maloperation of voltage dependent protection on AC voltage input failure.
•
CTS : Current transformer supervision - To raise an alarm should one or more of the
connections from the phase CTs become faulty.
•
46 BC : Broken conductor detection - To detect network faults such as open circuits,
where a conductor may be broken but not in contact with another conductor or the
earth.
•
50 BF : Circuit breaker failure protection - Generally set to backtrip upstream circuit
breakers, should the circuit breaker at the protected terminal fail to trip. Two stages
are provided.