L2234
Emax
44/158
Model
Scale
Page No.
Doc. No.
Apparatus
1SDH000460R0002
L2778
3.
Protection against instantaneous short-circuit“
I
”;
4.
Protection against closing on short-circuit “
MCR
”;
5.
Protection against earth fault with adjustable delay “
G
”;
6.
Protection against instantaneous short-circuit at high currents "
Iinst
";
7.
Protection against phase unbalance “
U
”;
8.
Protection against overtemperature “
OT
”.
The PR122/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 (m "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).
With the optional PR120/V module, the PR122/P unit also has the following protection functions:
9.
Protection against undervoltage “
UV
”;
10.
Protection against overvoltage “
OV
”;
11.
Protection against residual voltage “
RV
”;
12.
Protection against reverse active power “
RP
”;
13.
Underfrequency "
UF
";
14.
Overfrequency "
OF
".
13.2.6.1
Calculating the RMS
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 (6.3@2I
n
), the tolerance for the calculation of the true rms value will increase. With
the optional PR120/V module, the UV, OV, RV voltage protections always work on the basis of the true rms value of the voltages.
13.2.6.2
Mains frequency
The PR122/P unit constantly measures the frequency of the mains voltages it is connected to, only when a PR120/V module is installed.
If the frequency goes out of the permitted range by ±10% in relation to the rated frequency selected (50 or 60 Hz), the "warning" LED comes
on and the warning message is displayed (see par. 13.6.3).
The signal can be combined with a relay of the PR120/K module or with those of the PR021/K unit.
13.2.6.3
Harmonic distortion
The PR122/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.
13.2.6.4
Circuit-breaker state
If an auxiliary supply is used, or it is powered from the optional PR120/V, the PR122/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. 13.6) 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.
13.2.7 Measurement functions
The current measuring (ammeter) function is available on all versions of the SACE PR122/P unit.
The display shows histograms with the currents of the three phases and of the neutral on the main page. In addition, the current 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-supply mode and with an auxiliary power supply. In the latter case, or under self-powering for 3-phase currents
>300A ca. or when the PR120/V module is powered, the ammeter and backlighting are always active. The tolerance for the ammeter measuring
chain (current sensor plus relay) is described in paragraph 13.2.9.12.2.
- Currents: three phases (L1, L2, L3), neutral (N), earth fault.
- Instantaneous current values over a given time interval (data logger).
- Maintenance: number of operations, percentage of contact wear, opening data storage (latest 20 trips and 80 events).
- The protection records the historical data of the maximum current read.
When the optional PR120/V is connected, the following additional measurement functions are provided:
- 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.
- Maintenance: number of operations, percentage of contact wear, opening data storage.
- The protection records the historical data of the maximum and minimum phase-to-phase voltage, total maximum and mean active power
and total maximum and mean reactive power.
13.2.8 Watchdog
The PR122/P unit provides some watchdog functions able to guarantee the proper management of relay malfunctions. These functions are as
follows:
Watchdog for presence of Auxiliary power supply with "plug" icon displayed.
Rating PLUG validity.
Watchdog for proper connection of the current sensors (CS). If it is enabled, any anomalies are indicated by a special alarm message and
the "alarm" LED coming on, and the circuit-breaker opens after 1s.
Watchdog for proper connection of the Trip Coil (TC). If it is enabled, any anomalies are indicated by a special alarm message and the "alarm"
LED coming on; if the PR120/D-M module is installed, this activates the coil opening command (YO), thus opening the CB.
Watchdog for protection of Hw Trip. If it is enabled, in the event of the sensors being disconnected or a Rating Plug error, a CB opening command
is given by the TC being enabled.
