GE P444 User Manual

P
44x/EN AP/Hb6
Application Notes
(AP) 5
-152 MiCOM P40 Agile
P442, P444
If protection operates during the reclaim time, after the final reclose attempt, the relay will be
driven to lockout and the autoreclose function will be disabled until the lockout condition is
reset. This will produce an alarm, AR Lockout. Then, the DDB: 'BAR' input will block the
autorecloser and cause a lockout if a reclose cycle is in progress. Lockout will also occur if
the CB energy is low and that the CB fails to close. Once the autorecloser is locked out, it
will not function until a Reset Lockout or CB Manual Close command is received (depending
on the Reset Lockout method chosen in CB Monitor Setup).
Note: Lockout can also be caused by the CB condition monitoring functions maintenance
lockout, excessive fault frequency lockout, broken current lockout, CB failed to trip
and CB failed to close, manual close no check synchronism and CB unhealthy.
Figure 114: Trip signal still present when dead time elapses will force AR
lockout
5.10.1.1 Number of shot (trip mode cells) setting
There are no clear-cut rules for defining the number of shots for any particular application.
To determine the required number of shots, the following factors must be taken into account:
• An important consideration is the ability of the circuit breaker to perform several trip
close operations in quick succession and the effect of these operations on the
maintenance period.
• The fact that 80 - 90% of faults are transient highlights the advantage of single shot
schemes. If statistical information for the power system shows that a moderate
percentage of faults are semi-permanent, further time-delayed autoreclose shots may
be used provided that system stability is not threatened.
The relay allows up to four reclose shots, ie. one high speed single pole autoreclose shot,
plus up to three time-delayed shots. All time-delayed shots have three-pole operation. The
scheme is selected in the relay menu as follows:
“1P Trip Mode” first shot second shot 3
rd
shot 4
th
shot
1 1P -- -- --
1 / 3 1P 3P -- --
1 / 3 / 3 1P 3P 3P --
1 / 3 / 3 / 3 1P 3P 3P 3P
“3P Trip Mode”
1 3P -- -- --
1 / 3 3P 3P -- --
1 / 3 / 3 3P 3P 3P --
1 / 3 / 3 / 3 3P 3P 3P 3P
“1P”: Single Pole autoreclose shot
“3P”: Three Pole autoreclose shot
“--”: No shot.
Table 13: Reclosing scheme for single phase trips
If single pole and three pole autoreclose are enabled, then:

GE P444 Specifications

General

Brand	GE
Model	P444
Category	Protection Device
Language	English