Changing protection functions. Crate LS1-131

12.5.3. Changing protection functions

This paragraph enables the user to set the protection functions implemented in the PR121/P unit. Only the setting methods and which values can be selected are explained here. For all other information on the technical characteristics of the protection functions, see par. 12.2.5.

WARNING: No parameter settings can be made if the PR121/P unit is in alarm conditions.

12.5.3.1. Example of settings

In the diagrams on the front plate (see par. 12.5) relating to the settings, the position of the DIP switch is indicated by the white part.

An example of how to set the DIP switch for the protection function L is given below, where I n

= 2000A:

Frequency I

n

N

I

1

t

1

x 3 I

1

60 Hz

+

x I

n

50 Hz

I1 = 0,4 + 0,025 x In

I1 = 850A t1 = [email protected] (3*I

1

)

I

Frequency = 50 Hz n

N = 50%

A faulty configuration of the dip-switches generates a “Settings Inconsistency” error which is signalled by means of a LED (see par. 12.7.1).

Comply with this formula: I1<I2<I3.

E.g.: if I1 = 1In and I2 = 1In, the relay signals a “Settings Inconsistency” error. The same occurs when I2 = 5In and I3 = 4In.

12.5.4. PR121/P default settings

The PR121/P is supplied by ABB SACE with the following preset parameters:

# Protection

1

2

3

4

L

S

I

G

5

6

Mains frequency

Neutral sel

Note:

* = Off for 3-pole versions

* = 50% for 4-pole versions

* = 100% for full-size versions

Threshold

1 In

Off

4 In

Off

50 Hz

*

Time

144 s

0,1 s

--

0,1 s

12.6. Operating instructions / Operation in service

12.6.1. Neutral adjustment

The neutral protection is normally set to a current value 50% of the adjustment made on the phases.

In some installations, where particularly high harmonics occur, the current circulating on the neutral may be higher than that of the phases.

In the SACE PR121/P release, this protection can be set for the following values: I n

N =Off - 50% - 100% - 200% * I n

.

WARNING: With three-pole circuit-breakers, without external neutral sensor, the adjustment of the neutral must

be set to OFF.

12.6.2. Neutral adjustment specifications

To adjust neutral (I n

N) comply with the following formula: I

1 x I n

NIu.

With a 4-pole CB, this setting is checked by the relay which signals any failure by means of a LED (see par. 12.7.1) and independently adjusts this parameter, restoring it to within the accepted limits.

With a 3-pole CB, with external neutral, the relay performs no checks and setting is to be done by user.

E.g.: With E1B800 CB having a 400A Rating Plug, Iu = 800A and I1 = 1In, I n

With E1B800 CB having a 800A Rating Plug, Iu = 800A and I1 = 1In I n

N adjustment may be: 50-100-200% .

N adjustment may be: 50-100%.

Note 1: I

1

=1I n

setting is intended as the maximum adjustment of the protection against overloads. Actual maximum allowable adjustment must take into account any temperature derating, terminals used and altitude, or In (rating plug)≤ 50% of circuit breaker size.

WARNING: Failure to comply with the setting limits for “I

1 sequent risks to the operator too.

” and “I n

N” can damage the circuit-breaker, with con-

Model L2234

L2778

L4681

L5179

L5439

Apparatus

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