Checking Ct Circuits; Checking Vt Circuits - ABB RET650 Series Commissioning Manual

1MRK 504 136-UUS B
4.7

Checking CT circuits

• Primary injection test to verify the current ratio of the CT, the correct wiring up to the
protection IED and correct phase sequence connection (that is A, B, C.)
• CT secondary loop resistance measurement to confirm that the current transformer
secondary loop DC resistance is within specification and that there are no high resistance
joints in the CT winding or wiring.
• Grounding check of the individual CT secondary circuits to verify that each three-phase set of
main CTs is properly connected to the station ground and only at one electrical point.
• Insulation resistance check.
4.8

Checking VT circuits

Check that the wiring is in strict accordance with the supplied connection diagram.
Test the circuitry.
Transformer protection RET650
Commissioning manual
Be sure to set the correct technical key in both the IED and PCM600 to prevent
writing an application configuration to a wrong IED.
See the engineering manual for information on how to create or modify an
application configuration and how to write to the IED.
Check that the wiring is in strict accordance with the supplied connection diagram.
CT and VT connectors are pre-coded, and the CT and VT connector markings are
different. For more information, see the installation manual.
Both the primary and the secondary sides must be disconnected from the line and
the IED when plotting the excitation characteristics.
Correct possible errors before continuing to test the circuitry.
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Section 4
Starting up
M12182-2 v13
M11724-2 v8
33