The targets display the latest relay element condition at the time of tripping. For example,
zone targets illuminate if the current setting for that zone of protection is exceeded when
tripping occurs. If a new fault occurs, the targets show the new fault.
To clear the targets, press the TARGET RESET button. All eight indicators illuminate for
approximately one second as a lamp test. If they do not, the relay is disabled due to a self
test failure. After a new fault occurs, the targets are cleared before the new fault targets are
presented, so targets show the most recent fault. Pressing the TARGET RESET button
unlatches the TRIP output. This feature is useful during relay testing and minimizes the risk
of installing the relay with the TRIP output asserted.
SELF TESTS
The relay runs a variety of self tests. Some tests have warning and failure states; others only
have failure states. The relay generates a report after any change in self test status.
The relay closes the ALARM contacts after any self test fails. When it detects certain
failures, the relay disables the breaker control functions and places the relay output driver port
in an input mode. No outputs may be asserted when the instrument is in this configuration.
The relay runs all self tests on power up and before enabling new settings. During normal
operation, it performs self tests at least every few minutes.
Offset
The relay measures the offset voltage of each analog input channel and compares the value
against fixed limits. It issues a warning when offset is greater than 50 millivolts in any
channel and declares a failure when offset exceeds 75 millivolts. Offset levels for all channels
appear in the STATUS command format.
Power Supply
Power supply voltages are limit-checked. The table below summarizes voltage limits.
Table 2.7: Power Supply Self Test Limits
Supply
Warning Thresholds
+ 5 V
+5.3 V +4.7 V
+ 1 5 V
+15.8 V + 14.2 V
-15 V
-15.8 V -14.2 V
Failure Thresholds
+5.4 V +4.6 V
+16.2 V +13.8 V
-16.2 V -13.8 V
2-18
Specifications
SEL-267D/167D Instruction Manual
Date Code 920326
Summary of Contents for SEL-167D
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