Checking Vt Circuits; Checking The Rtxp Test Switch - ABB RELION 630 Series Comissioning Manual

Section 2
Starting up
2.8
2.9
16

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.

Checking the RTXP test switch

The RTXP test switch is designed to provide the means of safe testing of the IED. This
is achieved by the electromechanical design of the test switch and test plug handle.
When the test plug handle is inserted, it first blocks the trip and alarm circuits then it
short circuits the CT secondary circuit and opens the VT secondary circuits making
the IED available for secondary injection.
When pulled out, the test handle is mechanically stopped in half withdrawn position.
In this position, the current and voltage enter the protection, but the alarm and trip
circuits are still isolated. Before removing the test handle, check that no trip or alarms
are present in the IED.
The trip and alarm circuits are not restored for operation until the test handle is
completely removed.
By pulling in all cables, verify that the contact sockets have been
crimped correctly and that they are fully inserted. Never do this with
current circuits in service.
1MRS756801 E
630 series
Commissioning Manual