8.3 Current measurement module
Figure. 8.3 - 220. 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.
A basic current measurement module with five channels includes three-phase current measurement
inputs as well as coarse and fine residual current inputs. The CT module is available with either
standard or ring lug connectors.
The current measurement module is connected to the secondary side of conventional current
transformers (CTs). The nominal current for the phase current inputs is 5 A. The input nominal current
can be scaled for secondary currents of 1…10 A. The secondary currents are calibrated to nominal
currents of 1 A and 5 A, which provide ±0.5 % inaccuracy when the range is 0.005…4 ×
I
n
.
The measurement ranges are as follows:
• Phase currents 25 mA…250 A (RMS)
• Coarse residual current 5 mA…150 A (RMS)
• Fine residual current 1 mA…75 A (RMS)
The characteristics of phase current inputs are as follows:
• The angle measurement inaccuracy is less than ± 0.2 degrees with nominal current.
• The frequency measurement range of the phase current inputs is 6…1800 Hz with standard
hardware.
• The quantization of the measurement signal is applied with 18-bit AD converters, and the
sample rate of the signal is 64 samples/cycle when the system frequency ranges from 6 Hz to
75 Hz.
For further details please refer to the "Current measurement" chapter in the “Technical data” section of
this document.
A
AQ
Q-T215
-T215
Instruction manual
Version: 2.04
363
