Siemens 7UT51 User Manual

7UT51 v3
Motor or Generator Differential Protection (87M/G)
5
PRIM-2330C 75
5.7 Time Delays
If an 87M/G pickup occurs, the 87M/G function will
immediately trip unless a corresponding time delay
has been set in Address 1725.
To ensure that the trip state lasts long enough for the
circuit breaker to operate, the trip state can be
prolonged by a reset time delay that is set in
Address 1727.
5.8 Events and Actions
Table 5.1 describes the events that control and are
generated by the 87M/G function. They are listed in
the order that they are likely to occur, which is roughly
in numerical order by their event identification number
(shown in the “Event” column). The text in the “LCD
Abbreviation” column is the corresponding text that will
appear when viewing logs on the front panel LCD
display. In the “Oper” column, a letter “C” or “G”
indicates that the “Coming” and/or “Going” events are
logged in the Operational Log, while if in the “Fault”
column they indicate that the events are logged in the
open fault log. A letter in the “In/Out” column indicates
that the event can be controlled by a binary-signal
input (“I”), control an LED and/or signal contact (“S”),
and/or control a trip contact (“T”).
1725 87 DELAY
Time delay between pickup and trip for 87
differential protection (in addition to the
inherent operating time of the relay).
Range: 0.00
–
60.00 s, or ∞
Default: 0.00 s
1727 T
-
RESET
Additional time to remain in trip state after the
87 function trip state disappears (in addition
to the inherent reset time of the relay).
Range: 0.00
–
60.00 s
Default: 0.10 s
Motor or Generator Differential Protection (87M/G) Occurrence LCD Abbreviation Event Oper Fault In/Out
Change in Operational Status
When the operational status of the 87M/G function changes, a
going
-
event for the old status occurs followed by a coming
-
event
for the new status. The normal operational status is set in
Address 1701.
87Diff OFF
87Diff BLOCK
87Diff ACTIVE
5615
5616
5617
C
C
C
G
G
G
S
S
S
A binary input can temporarily change the operational status of the
function (see Section 13.2 on page 126). Any outputs marshalled
to these events will remain actuated for as long as the binary input
remains actuated.
>87Diff BLOCK
>87DiffBlkTrip
5603
5605
I
I
S
S
Pickup and Dropout
If the operating point of any phase rises above 85% of the setting
threshold of the pickup characteristic, or if the restraint current
(I
rest
) exceeds four times rated nominal current (I
n
), the 87M/G
function will pickup (event 5631C). If no fault log is already open, a
new one will open.
If the operating point for all phases remains below 70% of the
setting threshold of the pickup characteristic for two full cycles, the
87M/G function will dropout (event 5631G). See Section 5.4 on
page 71.
87Diff GenFlt 5631 CG S T
An 87M/G phase
-
pickup occurs if the operating point of a phase
rises above the pickup characteristic. Outputs marshalled to these
events will remain actuated until dropout of the corresponding
phase.
87Diff PhA
87Diff PhB
87Diff PhC
5681
5682
5683
C
C
C
S
S
S

Siemens 7UT51 Specifications

General

Brand	Siemens
Model	7UT51
Category	Relays
Language	English