SMC Networks raptor User Manual page 57

shown in the diagram.
With this connection, the phase angle between primary and secondary must be zero or
very close to this value, indicating correct polarity. It is important to connect the voltage
measurement directly to the CT secondary output bushings to include the entire burden of
the CT, and not just part of it, in that measurement. (See diagram)
DANGER – Make sure that the CT secondary is properly
connected to its receivers. Injecting current into the primary
with an open secondary is very risky both for the CT and for
the operator, as the CT may even explode.
Test:
Select and inject the desired current. The timer will start up. When the countdown
reaches zero, the injection will stop.
If you wish to test another point of the CT, repeat the process at another current value.
When testing a CT, it is usually advisable to test the ratio error and phase angle at
different primary currents, above all if this is a measurement CT. It is advisable to do this
at 120%, 100%, 50% and 20% of its nominal current. If it is a Protection CT it is more
important to test the ratio at the highest possible points permitted by your RAPTOR
system, apart from at 100%.
If you observe that the measurements are unstable, and the values are continuously
changing, use the Filter option to see the most stable values.
If you find the default measurement time established on the Template
(8 s) short and you wish to increase it, do so, but bear in mind the
cable cross-section used (the cable may overheat) and above all, the
overcurrent values and the maximum time supported by the CT being
tested without a risk of damage.
Users Guide
57