ABB RET670 Commissioning Manual page 221

1MRK 504 165-UEN A
Transformer protection RET670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
1. Check that the IED settings are appropriate, for example the start value and
the time delay.
2. Supply the IED with three-phase voltages at their rated values and initial
frequency.
The initial frequency is calculated using Equation 102.

StartFrequency 0.02
IECEQUATION16059 V1 EN-US
3. Slowly decrease the voltage frequency by steps of 40 mHz until the START
signal appears; during each step apply the voltage signal for a time that is
either at least 10% longer than (tDelay+100ms) or a suitable time to monitor
the function.
4. Note the frequency value at which the START signal appears and compare it
with the set value StartFrequency.
5. Increase the frequency until its rated value is reached.
6. Check that the START signal resets.
7. Supply the IED with three-phase voltages at their rated values and frequency
20 mHz over the set value StartFrequency.
8. Decrease the frequency with a 40 mHz step, applying it for a time that is at
least 10% longer than (tDelay+100ms).
9. Measure the time delay of the TRIP signal, and compare it with the set value
tDelay. Note that the measured time consists of the set value of the time delay
plus the minimum operate time of the start function (80 - 90 ms).
Extended testing
1. The test above can be repeated to check the time to reset.
2. The tests above can be repeated to test the frequency dependent inverse time
characteristic.
Verification of the low voltage magnitude blocking
1. Check that the IED settings are appropriate, for example the StartFrequency,
UMin , and the tDelay.
2. Supply the IED with three-phase voltages at rated values.
3. Slowly decrease the magnitude of the applied voltage, until the BLKDMAGN
signal appears.
4. Note the voltage magnitude value and compare it with the set value UMin.
5. Slowly decrease the frequency of the applied voltage, to a value below
StartFrequency.
6. Check that the START signal does not appear.
7. Wait for a time corresponding to tDelay, make sure that the TRIP signal does
not appear.
  
floor f StartFrequency / 0.04

r
Section 11
 
0.04

(Equation 102)
M16289-31 v6
M16289-39 v7
215