Self-Test Errors - GE 845 Instruction Manual

CHAPTER 3: INTERFACES

Self-test Errors

CAUTION:
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
The target message interrupts the message timeout. It overrides it. The message timeout
starts timing after each target message, and if no more activity is recorded for the
specified time, the display goes back to the default screen.
Pressing a programmable pushbutton activates a new screen with a Target Message
corresponding to the programmed PB action. The PB Target Message is displayed for 10
seconds then defaults to the screen that was displayed before pressing the pushbutton.
The PB Target Message is recorded in the list with other generated Target Messages.
Target Messages can be cleared either by pressing the PB corresponding to the tap
"CLEAR", or by initiating a RESET command. The "CLEAR" command clears only the Target
Messages, while initiating a RESET clears not only the Target Messages, but also any
latched LEDs and output relays.
The relay performs self-diagnostics at initialization (after power up), and continuously as a
background task to ensure that the hardware and software are functioning correctly.
There are two types of self-test warnings indicating either a minor or major problem. Minor
errors indicate a problem with the relay that does not compromise protection and control
functionality of the relay. Major errors indicate a problem with the relay which takes it out
of service.
Self-Test Warnings may indicate a serious problem with the relay hardware!
Upon detection of a minor problem, the relay does the following:
• Displays a detailed description of the error on the relay display as a target message
• Records the minor self-test error in the Event Recorder
• Flashes the "ALARM" LED
Upon detection of a major problem, the relay does the following:
• De-energizes critical failure relay
• Inhibits operation of all output relays and freezes the current state
• Blocks protection and control elements
• Turns the "IN SERVICE" LED to red
• Flashes the "ALARM" LED
• Displays "Major Self-test error" with the error code as a target message
• Records the major self-test failure in the Event Recorder
Under both conditions, the targets cannot be cleared if the error is still active.
Figure 3-9: Minor Errors
FRONT CONTROL PANEL INTERFACE
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