8.3. Current measurement module
Figure. 8.3. - 178. Current measurement module connections with standard and ring lug terminals.
Connector
Description
CTM 1-2
Phase current measurement for phase L1 (A)
CTM 3-4
Phase current measurement for phase L2 (B)
CTM 5-6
Phase current measurement for phase L3 (C)
CTM 7-8
Coarse residual current measurement I01
CTM 9-10
Fine residual current measurement I02
Basic ve channel current measure module includes three phase current measurement inputs and
coarse and ne residual current inputs. CT module is available with either standard or ring lug
connectors.
Current measurement module is connected to secondary side of conventional current transformers
(CTs). Nominal dimensioning current for the phase current inputs is 5 A. Input nominal current can be
scaled for secondary currents of 1…10 A. Secondary currents are calibrated to nominal currents of 1A
and 5A which provide ± 0.2% inaccuracy in range of 0,05 x In – In – 4 x In.
Phase current input characteristics are as follows:
Measurement range
Phase currents 0…250 ARMS
Coarse residual current 0…150ARMS
Fine residual current 0…75ARMS
Angle measurement accuracy less than ± 0.5 degrees with nominal current.
Frequency measurement range of the phase current inputs is in range from 6 Hz to 1800 Hz
with standard hardware.
Quantization of the measurement signal is applied with 18 bit AD converters and the sample
rate of the signal shall be 64 samples / power cycle in system frequency range of 6 Hz to 75 Hz.
For further details refer to the “Technical data” section of this document.
AQ-T257
Instruction manual
Version: 2.00
313
© Arcteq Relays Ltd
