ABB RELION REX640 Operation Manual page 155

1MRS759118 D
testing from the measurement and trip circuits. Each protection function is then
tested one by one to confirm the functionality in respect of:
• start value level
• operate value level
• reset ratio value
• operate time, typically done with an infeed of 1,5 times the operate value setting
The results are compared to the setting values and the test records from the
commissioning and the latest periodical test results. In case discrepancies outside
the manufacturer's stated accuracy limits are found, the corresponding test shall be
repeated. If the second test results are still outside the limits, deeper considerations
are needed. If the deviation is considerable, recommendation is to replace the relay
with a spare relay. In case of a slight deviation the operation until the next periodical
test round can be considered.
The secondary test set will also introduce certain level of inaccuracies to the
tests, especially if the test set has not been calibrated as per the manufacturer's
instructions. As a final task for each protection function testing, it's highly
recommended to do final operate test including the circuit breaker operation. In
case the circuit breaker is equipped with two trip coils, the condition of both coils
shall be verified.
During the testing of protection functions, the related measurements and events
shall be verified from the local HMI. The verification, if possible, is recommended
to be extended all the way to the upper-level systems like Scada or process control
system.
When testing individual protection functions, there will be situations where some
other protection function might interfere the testing of the selected one. REX640
HMI under page "Testing and Commissioning" offers various support for testing
activities. By enabling IED Test mode and entering page "Secondary Injection
Monitoring" there is a possibility to disable selected protection function(s). When
the relay is returned to Normal mode, the functions will regain their original status
automatically.
The correct function and the related external circuitry of IRF-relay (internal relay
fault) output shall be checked. This can be performed using dedicated functionality
in the HMI. Under the page "Testing and Commissioning" there is a tab called
"Internal fault test". By selecting position "test on", the IRF-relay will be de-
energized, and the function of the related circuitry can be verified.
Arc flash sensors connected to REX640 relays include supervision functionality. This
functionality will indicate if the connected sensor's, loop or lens, optical circuit
is intact. It is recommended that each sensor, one by one, is disconnected from
the relay to check that the correct alarm and event information is received. The
supervision function is not able to detect if sensor is dirty or if the sensor is
misaligned due to mechanical impact, these shall be checked visually.
8.1.2.2 Recommended Testing Intervals
The recommended periodical testing interval is between three and five years,
depending on the following factors.
Installation environment
REX640 relays which are installed in harsh environments, we recommend applying
the three years interval. The harsh conditions can be due to temperatures and/or
REX640
Operation Manual
Maintenance and Periodical Testing
155