ABB REX610 - Checking CT and VT Circuits

8.2.3 Checking VT circuits
Check that the wiring is in strict accordance with the supplied connection diagram.
Correct possible errors before continuing to test the circuitry.
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
polarity must be measured as close to the protection relay as possible to ensure that
most of the wiring is also checked.
The primary injection test verifies the VT ratio and the wiring all the way from the
primary system to the protection relay. Injection must be performed for each phase-
to-neutral circuit and each phase-to-phase pair. In each case, voltages in all phases
and neutral are measured.
8.2.4 Checking binary input and output circuits
8.2.4.1 Checking binary input circuits
• Preferably, disconnect the binary input connector from the binary input cards.
• Check all the connected signals so that both the input level and the polarity are
in accordance with the protection relay specifications.
Binary inputs support also AC voltages.
8.2.4.2 Checking binary output circuits
• Preferably, disconnect the binary output connector from the binary output
cards.
• Check all connected signals so that both load and voltage are in accordance
with the protection relay specifications.
2NGA000823 A Section 8
Commissioning
REX610 69
Operation Manual