Alstom MiCOM P545 - 11. ON-LOAD CHECKS; 11.1 Confirm current and voltage transformer wiring; 11.1.1 Voltage connections

P54x/EN CM/La4 Commissioning
(CM) 10-62 MiCOM P543, P544, P545 & P546
CM
11. ON-LOAD CHECKS
The objectives of the on-load checks are to:
 Confirm the external wiring to the current and voltage inputs is correct
 Measure the magnitude of capacitive current
 Ensure the on-load differential current is well below the relay setting
 Check the polarity of the line current transformers at each end is consistent
 Directionality check for distance elements
However, these checks can only be carried out if there are no restrictions preventing the
energization of the plant being protected and the other P54x relays in the group have been
commissioned.
Remove all test leads, temporary shorting leads, etc. and replace any external wiring that
has been removed to allow testing.
If it has been necessary to disconnect any of the external wiring from the relay in order to
perform any of the foregoing tests, it should be ensured that all connections are replaced in
accordance with the relevant external connection or scheme diagram.
11.1 Confirm current and voltage transformer wiring
11.1.1
Voltage connections
Usi
ng a multimeter measure the voltage transformer secondary voltages to ensure they are
correctly rated. Check that the system phase rotation is correct using a phase rotation
meter.
Compare the values of the secondary phase voltages with the relays measured values,
which can be found in the MEASUREMENTS 1 menu column.
Voltage
Cell in MEASUREMENTS 1
Column (02)
Corresponding VT ratio in ‘VT
and CT RATIO‘ column (0A) of
menu)
VAB
VBC
VCA
VAN
VBN
VCN
[0214: VAB Magnitude]
[0216: VBC Magnitude]
[0218: VCA Magnitude]
[021A: VAN Magnitude]
[021C: VBN Magnitude]
[021E: VCN Magnitude]
[0A01 : Main VT Primary]
[0A02 : Main VT Secondary]
VCHECKSYNC. [022E: C/S Voltage Mag.]
[0A03 : C/S VT Primary]
[0A04 : C/S VT Secondary]
CB2
VCHECKSYNC.
[024C: CB2 CS Volt Mag]
(P446 only)
[0A05 : CB2 CS VT Prim’y]
[0A06 : CB2 CS VT Sec’y]
Table 14: Measured voltages and VT ratio settings
If cell [0D02: MEASURE’T. SETUP, Local Values] is set to ‘Secondary’, the values displayed
on the relay LCD or a portable PC connected to the front EIA(RS)232 communication port
should be equal to the applied secondary voltage. The values should be within 1% of the
applied secondary voltages. However, an additional allowance must be made for the
accuracy of the test equipment being used.