Specifications

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Doc. no.
Model
Apparatus
Scale
Page No
1SDH000460R0002
L5439
8. Protection against phase unbalance “U”;
9. Protection against overtemperature “OT”;
10. Protection against undervoltage “UV”;
11. Protection against overvoltage “OV”;
12. Protection against residual voltage “RV”;
13. Protection against reverse active power “RP”;
14. Underfrequency “UF”;
15. Overfrequency “OF”.
The PR123/P unit allows current signal processing of the neutral pole with different relationships relative to the value of the phases.
N.B.: Beyond 15.5xIn of current on the Ne, the protection is considered as being set to 100%.
A timing indication (message + “alarm” LED) is provided on the unit’s display, which is activated during a protection alarm. It is
disabled when the alarm condition ceases or when the protection has been tripped. When the circuit-breaker opens, the page
with the “Trip” data is displayed (when “i Test” is pressed, or automatically in the presence of Vaux).
14.2.6.1. Rms calculation
All the protection functions do their respective processing on the basis of the real rms value of the currents and voltages (the
protection G is disabled for current values greater than 8In [where I
4
 0,8In], greater than 6In [where 0,5In I
4
<0,8In] and greater
than 4In [where I
4
<0,5In]).
If the waveform has a deformation beyond the declared limit (see peak factor), the tolerance for the calculation of the true rms
value will increase. The UV, OV, RV voltage protections always work on the basis of the true rms value of the voltages.
14.2.6.2. Mains frequency
The PR123/P unit constantly measures the frequency of the mains voltages it is connected to.
If the frequency exceeds the permitted range the “warning” LED comes on and the warning message is displayed (see par. 14.6.3).
The signal can be combined with a relay of the optional PR120/K module or with those of the PR021/K unit.
14.2.6.3. Harmonic distortion
The PR123/P unit signals that a peak factor of 2.1 has been exceeded with a warning message and the “warning” LED lighting
up (remember that the IEC 60947-2 standard annex “F” establishes that the protection unit must function regularly with a peak
factor ≤ 2.1, up to 2xIn).
The signal can be combined with a relay of the PR120/K module or with those of the PR021/K unit.
14.2.6.4. Circuit-breaker state
The PR123/P unit records the state of the circuit-breaker by means of specific wiring on the circuit-breaker. In the case where the
presence of current is determined with the circuit-breaker in the “OPEN” state, a state error is signaled by a warning message
being displayed (see par. 14.6) and the “warning” LED lighting up.
The signal can be combined with a relay of the PR120/K module or with those of the PR021/K unit.
14.2.7. Measurement functions
The current measuring (ammeter) function is available on all versions of the SACE PR123/P unit.
The display shows histograms with the currents of the three phases and of the neutral on the main page. In addition, the cur-
rent of the phase under the greatest load is given in numerical form. Where applicable, the earth fault current is displayed on a
separate page.
The ammeter functions both in self-powering mode and with an auxiliary supply. In the latter case or in the event of self-powering
for 3-phase currents >300A ca. or when the PR120/V module is installed and powered, ammeter and backlighting are always
active. The tolerance for the ammeter measuring chain (current sensor plus ammeter) is described in paragraph 14.2.9.16.
The PR123/P release provides a complete set of measurements:
- Currents: three phases (L1, L2, L3), neutral (Ne), earth fault
- Voltage: phase-phase, phase-neutral, residual voltage
- Instantaneous voltage values over a given time interval (data logger)
- Power: active, reactive, apparent
- Power factor
- Frequency and peak factor
- Energy: active, reactive, apparent
- Harmonics calculation: up to the fortieth harmonic (waveform and module of the harmonics displayed); up to the thirty-fifth for
frequency f=60Hz
- Maintenance: number of operations, percentage of contact wear, opening data storage.
- Data Logger: see par. 16.3.
The PR123/P can provide the trend of the measurements of certain quantities over an interval P, established by the user; these
include: mean active power, maximum active power, maximum current, maximum voltage and minimum voltage. The last 24 P
intervals (adjustable from 5 to 120 min) are stored in a non-volatile memory and displayed in a bar graph.
To examine the Measurement functions, see the relevant paragraphs (par. 15.1 and par. 14.5.3) for the PR120/V - MEASURING
module.