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6. Technical data
6.1. Analog inputs
6.1.1. Measurements
The REF 542plus unit uses the same analog inputs both for measurements and
protections.
Table 6.1.1.-1 Measurements
Quantity Class Range
Phase current, earth current 0.5 0.1-4I
n
Line voltage, phase voltage 0.5 0.2-1.5V
n
Active, reactive energy 2 -
Active, reactive, apparent power 1 -
Cosφ 1 –1-+1
Frequency 0.02 40-75 Hz
To achieve highest accuracy the instrument transformers or the sensors must have
0.5 percent accuracy or better in the same range.
6.1.2. Protection
Table 6.1.2.-1 Protection functions and operation time
Protection functions Class 3
Operation time Class 3 or minimum ±15 ms
Table 6.1.2.-2 Current and voltage transformer input values
Rated current l
n
0.2 A or 1A or 5 A
Rated voltage U
n
100 V - 125 V
Rated frequency f
n
50 Hz or 60 Hz
Table 6.1.2.-3 Thermal load capacity
Current path 250 I
n
(peak value), dynamic 100 I
n
for 1s,
4I
n
continuous
Voltage path 2 U
n
/√3 continuous
Table 6.1.2.-4 Consumption
Current path ≤ 0.1 VA with I
n
Voltage path ≤ 0.25 VA with U
n
Multifunction Protection and Switchbay Control
Unit
Technical Reference Manual
REF 542plusREF 542plus
1MRS755859