P92x/EN CM/E11 Techncal Guide
Commissioning Guide
Page 14/28 MiCOM P921-P922-P923
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4.2.7 Voltage inputs
This test verifies the accuracy of voltage measurement is within the acceptable
tolerances.
4 types of connection are possible for the MiCOM P921, P922 and P923 relays: 3VT
(phase-neutral), 3VT (phase-phase) + residual VT, 3VT (phase-neutral) + residual VT,
2VT (phase-phase) + residual VT.
THE FOLLOWING TESTS ARE PERFORMED WITH A 3VT CONNECTION
(PHASE-PHASE) CORRESPONDING TO THE MOST FREQUENT
CONFIGURATION.
Apply the rated voltage to each voltage input. Check its magnitude using a
multimeter. Refer to Table 6 for the corresponding reading in the relay's
"MEASUREMENTS" menu and record the value displayed.
MEASUREMENTS menu Voltage applied to
VA (RMS value) 41-42
VB (RMS value) 43-44
VC (RMS value) 45-46
TABLE 6 : VOLTAGE INPUT TERMINALS
The measured voltage values on the relay will be in primary volts.
The measurement accuracy of the relay is ±1%. Nevertheless, additional allowance
must be made for the accuracy of the test equipment being used.
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