Crate LS1-131 Especificações descarregar pdf (Página 40)

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12.2.2.2. Auxiliary power supply

The outside auxiliary power supply is provided using a galvanically-separated power pack.

WARNING: 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 3.5 mA.

The presence of the auxiliary power supply enables the relay unit to be used even with the circuit-breaker open.

The characteristics of the power pack are given in the table below:

Characteristics Version PR121/P

Auxiliary voltage (galvanically separated) 24 V DC ±20%

Maximum ripple 5%

Inrush current @ 24V ~10 A for 5ms

Rated power @ 24V ~1 W

12.2.3. Environmental characteristics

Operating temperature -25 °C ... +70 °C

Storage temperature -40 °C ... +70 °C

Relative humidity 0% ... 98% with condensation

Degree of protection (with PR121/P installed in the circuit-breaker) IP 30

12.2.4. Communication bus

Local bus on rear connector; RS485 physical interface, Modbus protocol.

Test bus on front test connector.

12.2.5. Protection functions

The PR121/P unit provides 5 independent protection functions, i.e.:

1. protection against overload with inverse time “L”;

2. protection against short-circuit with adjustable delay “S”;

3. protection against instantaneous short-circuit “I”;

4. protection against earth fault with adjustable delay “G”;

5. protection against instantaneous short-circuit at high currents “Iinst”.

The PR121/P unit allows the neutral pole’s current signal to be processed using different relationships with 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 (“alarm” LED) is provided on the front of the unit, which is enabled during an alarm for each protection; it is

disabled when the alarm condition ceases or when the protection has been tripped.

The unit also has a “backup protection” function. If the circuit-breaker does not open immediately the first time the Trip Coil is hit

(partial TC failure), TRIP commands are sent repeatedly until the circuit-breaker opens.

For the inverse-time protections, the relationship between trip time and overcurrent is given by the formula: t=k/I

For the fixed-time protections with an adjustable delay, the relationship adopted is as follows: t=k.

12.2.5.1. Calculating the RMS

All the protection functions do their respective processing on the basis of the real rms value of the currents (the protection G

is disabled for current values greater than 8In [where I4>0,8In], greater than 6In [where 0.5In≤ I4<0.8In] and greater than 4In

[where I4<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.

12.2.5.2. Measuring Function

A current measuring function (ammeter) is available on all versions of the PR121/P unit.

This function can be accessed through a PR10/T test unit only via a test bus and through HMI030 via a local bus.

With auxiliary voltage, the protection records a historical of the maximum current read.

12.2.5.3. Watchdog

The PR121/P unit provides some watchdog functions to guarantee the proper management of relay malfunctions. These func-

tions are as follows:

 RATING PLUG validity.

 Watchdog for proper current sensor connection (CS). Any anomalies are indicated by the LED coming on, as explained in par.

12.7.1.

 Watchdog for proper opening solenoid connection (TC). Any anomalies are indicated by the LED coming on, as explained in

par. 12.7.1.

 Watchdog for protection against Hw Trip. If the sensors are disconnected or there is a Rating Plug error, when activated, a CB

opening command is issued due to the TC being activated. This function can be activated through a PR010/T test unit.

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