L2234
Emax
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Model
Scale
Page No.
Doc. No.
Apparatus
1SDH000460R0002
L2778
With the optional PR120/V module, the PR122/P also assures the following protections:
Symbol
Protection against
UV
undervoltage
OV
overvoltage
RV
residual voltage
RP
reverse active power
UF
underfrequency
OF
overfrequency
U
phase-to-phase voltage unbalance (as an alternative to phase currents)
13.2.2 Electrical characteristics
Rated operating frequency
50/60 Hz ±10%
Pass band
3000 Hz max
Peak factor
6.3 max @ 2In
MTBF (MIL-HDBK-217E)
15 years @ 45°C
13.2.2.1
Self-supply
The self-supply enables the protection unit to be powered with the busbar current using current transformers.
Using this supply mode, the unit's protection functions are assured, however, not the accessory functions regarding the modules.
The characteristics are given in the table below:
General characteristics
Relay Enabling Display Switch-On
E1...E3
E4...E6
E1...E3 E4...E6
Minimum three-phase busbar current for enabling relay and switching on the display >70A
>140A
>160A >320A
13.2.2.2 Auxiliary power supply
The external auxiliary power supply is provided using a galvanically-separated power pack.
Since the auxiliary voltage needs to be isolated from the ground, "galvanically separated converters" in accordance with
the IEC standard 60950 (UL 1950) or the equivalent IEC 60364-41 and CEI 64-8 have to be used to guarantee a current in
common mode or leakage current (as defined in IEC 478/1 and CEI 22/3) no greater than 3.5mA.
The presence of the auxiliary power supply enables the relay unit to be used even with the circuit-breaker open, as well as powering all the modules.
The characteristics of the power pack are given in the table below:
Characteristics
Version PR122/P
Auxiliary voltage
(galvanically separated)
24V DC ±20%
Maximum ripple
5%
Inrush current @ 24V
~10 A for 5ms
Rated power @ 24V
~5W
13.2.2.3
Powered by the PR120/V module
For a full explanation of the features of the PR120/V, see par. 15.1.
13.2.3 Environmental characteristics
Operating temperature
-25°C ... +70°C
Storage temperature
-40°C ... +90°C
Relative humidity
0% ... 98% with condensation
Degree of protection (with PR122/P installed in the CB)
IP 30
13.2.4 Description of inputs/outputs
13.2.4.1
Binary inputs
–
K51/SZin:
Zone selectivity: input for protection S
(only with Vaux)
–
K51/Gzin:
Zone selectivity: input for protection G
(only with Vaux)
13.2.4.2
Binary outputs
–
K51/SZout:
Zone selectivity: output for protection S
(only with Vaux)
–
K51/GZout:
Zone selectivity: output for protection G
(only with Vaux)
Note: These inputs/outputs should be used between PR122/PR123 and PR332/PR333 series units only.
13.2.5 Communication bus
Local bus on rear connector; RS485 physical interface, Modbus protocol.
External system bus, RS485 physical interface, Modbus RTU protocol, baud rate 9600-19200 bps.
Test bus on front test connector.
13.2.6 Protection functions
The PR122/P protection unit carries out 8 independent protection functions. In particular:
1.
Protection against overload with inverse time “
L
”;
2.
Protection against short-circuit with adjustable delay “
S
”;