ABB RET670 Commissioning Manual page 119

1MRK 504 165-UUS -
Transformer protection RET670 2.2 ANSI
Commissioning manual
Measure operating characteristics during constant current conditions. Keep the measured
current as close as possible to its rated value or lower. But make sure it is higher than the
set minimum operating current.
Ensure that the maximum continuous current to the IED does not exceed four times its
rated value, if the measurement of the operating characteristics runs under constant
voltage conditions.
The test procedure has to take into consideration that the shaped load encroachment
characteristic is active. It is therefore necessary to check the setting. To verify the settings
with the shaped load encroachment characteristic the test should be carried out according
to figures 23 and 24 and tables
characteristic is activated tests according to the adjusted figures should be carried out.
To verify the settings for the operating points according to the following fault types should
be tested:
• One phase-to-phase fault
• One phase-to-ground fault
The shape of the operating characteristic depends on the values of the setting parameters.
The figures illustrating the characteristic for the distance protection
function can be used for settings with and without load encroachment. The
solid lines designate the diagram applicable when the load current
compensation is active. The solid line and all test points except 13 are
valid for this case.
When the load current compensation is inactive, the dotted lines and test
point 13 are valid. Test points 5, 6, and 7 are not valid for this
measurement.
Testing functionality by secondary injection
18 and 19. In cases where the load encroachment
Section 11
113