GE 745 Instruction Manual page 231

CHAPTER 6: ACTUAL VALUES
6.6 Target and Flash Messages
6.6.1 Target Messages
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
Target messages are displayed when any protection, monitoring or self-test target is
activated. The messages contain information about the type of the active target(s), and are
displayed in a queue that is independent of both the setpoint and actual value message
structures.
When any target is active, the Message LED will turn on, and the first message in the queue
is displayed automatically. The target message queue may be scrolled through by pressing
the MESSAGE DOWN and UP keys.
As long as there is at least one message in the queue, the Message LED will remain lit.
Pressing any key other than MESSAGE DOWN or UP will return the display to the setpoint or
actual value message that was previously displayed. The MESSAGE DOWN and UP keys
may be pressed any time the Message LED is lit to re-display the target message queue.
If the MESSAGE RIGHT key is pressed when no target messages are in the queue, the
following flash message will appear:
NO ACTIVE TARGETS
A typical active target message looks like this,
 LATCHED: a
 Percent Differentl
and consists of three components which are arranged as follows:
 <STATUS>: <PHASE>
 <CAUSE>
The part of the above message will be one of
<STATUS>
• PICKUP: Indicates that the fault condition that is required to activate the protection
element has been detected by the 745 but has not persisted for a sufficiently long
time to cause the relay to activate its protection function.
• OPERATE: Indicates that the protection element has been activated.
• LATCHED: Indicates that the protection element is (or was) activated. This display will
remain even if the conditions that caused the element to activate are removed.
The part of the message represents the phase(s) that are associated with the
<PHASE>
element (where applicable).
Messages for targets remain in the queue until the relay is reset. Messages for
LATCHED
and targets remain in the queue as long as the condition causing the
PICKUP OPERATE
target to be active is present. In addition, messages for
be deleted if an entire week passes without any changes to the state of the target
messages but the conditions that caused the
are no longer present.
The bottom line of the display (i.e.,
activated. These are as follows:
TARGET AND FLASH MESSAGES
PICKUP
LATCHED
LATCHED messages to be displayed originally
) will be the name of the element that has been
<CAUSE>
, or :
OPERATE LATCHED
targets will automatically
6–23