Checking Ct Circuits; Checking Vt Circuits - ABB Relion 650 Series Commissioning Manual

Section 2
Starting up
2.7
2.8
24
See the engineering manual for information on how to create or
modify an application configuration and how to write to IED.
Set setting parameters through the LHMI. See the operation manual
for information on how to change a setting from the LHMI.

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 L1,
L2, L3.)
• 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.
• Earthing check of the individual CT secondary circuits to verify that each three-
phase set of main CTs is properly connected to the station earth and only at
one electrical point.
• Insulation resistance check.
Both primary and secondary sides must be disconnected from the
line and IED when plotting the excitation characteristics.

Checking VT circuits

Check that the wiring is in strict accordance with the supplied connection diagram.
Do not continue before any errors are corrected.
Test the circuitry.
• Polarity check
• VT circuit voltage measurement (primary injection test)
• Earthing check
• Phase relationship
• Insulation resistance check
The polarity check verifies the integrity of circuits and the phase relationships. The
check should be performed as close to the IED as possible.
1MRK 511 209-UEN -
REC650
Commissioning Manual