Thermal Memory S; Protection I; Protection G; Neutral Protection - ABB Emax E1 Installation And Service Instructions Manual

real tripping time is forced to t
NOTES:
- t(s)= envisaged tripping time;
- I = fault current; given in [In] (example: 1.7In)
f
- I , t = protection S parameters set by the user, given in [In] and [s]
2 2

12.4.2.1. Thermal memory S

The thermal memory function can be enabled for cable protection when the curve with inverse time is selected. This is based on
the "tS" parameter defi ned as the trip time of the curve (t2) selected at 1.5xI2. The other characteristics are the same as those
for thermal memory "L".

12.4.3. Protection I

This protection can be disabled; it is of the fi xed time (t=k) type, and is designed for a nil intentional delay.

12.4.4. Protection G

The protection, which can be disabled, can be the fi xed time (t=k) or inverse time (t=k/I
The tripping time with inverse time curve is given by the expression: t(s)=
tripping time is forced to t
NOTES:
- t(s)= envisaged tripping time;
- I = fault current; given in [In] (example: 3.7In)
f
- I , t = protection G parameters set by the user, given in [In] and [s]
4 4
The PR121/P unit can provide earth fault protection, achieved inside the relay by vectorially adding together the phase and neutral
currents. The fault current is defi ned by the following formula:
If there is no fault in the circuit, the modulo-sum of these currents is always nil.
Vice versa, the fault current will acquire an increasingly higher value, depending on the entity of the fault.
WARNING: protection G is disabled for current values exceeding 8In (for I
I <0,8In) and higher than 4In (for I
4
ATTENZIONE: With Iu800A: In the absence of Vaux and with I4<100A, the SW forces the minimum threshold to
100A and LED show "Settings inconsistency" error. With Iu250A: In the absence of Vaux and with I4<30A, the
SW forces the minimum threshold to 30A and LED show "Settings inconsistency" error.

12.4.5. Neutral Protection

Unit PR121/P allows the current signal of the neutral pole to be processed with different ratios in relation to the phase values.
The following values can be set for this protection: I
at a current value equal to 50% of the phase regulation.
Regulation of the neutral value (InN) must conform to the following formula: (I
The relay performs the test automatically for four-pole circuit-breakers and transmits a fault signal following failure to conform to
this formula. If the circuit-breaker is the three-pole type with external neutral, no tests will be performed by the relay and correc-
tion of the settings is at the user's charge.
E.g. With CB E1B800 (Iu=800A), Rating plug 400A (In=400A) and I1=1In, the I
With CB E1B800 (Iu=800A), Rating plug 800A (In=800A) and I1=1In, the I
The I =1I setting is the maximum setting of the protection against overload. The real permissible maximum setting must take
1 n
account of derating due to the temperature, terminals used and the altitude.
WARNING: In some installations, where particularly high harmonics occur, the current circulating on the neutral
may be higher than that of the phases.
WARNING: For three-pole circuit-breakers without external neutral, the Neutral protection setting must be Off,
otherwise the sensor presence error will be signalled (Error CS).
In these cases, connect T5-T6 to the sliding contacts, as shown in the wiring diagrams.
WARNING: Failure to comply with the setting limits for "I
consequent risks even for the operator.
WARNING: the protection setting is automatically 100% when the current value exceeds 15.5xIn on the neutral.
Model L6555
(t(s)= t .)
2 2
(t(s)= t ).
4 4
<0,5In)
4
2
(I /I
f
N =Off - 50% - 100% - 200% * I
n
1
" and "I
1
Apparatus
Doc. No
2 ) type.
; If the calculated value is less than t
2
)
4
0,8In), higher than 6In (for 0,5In
4
. The neutral protection is set by default
n
N) Iu.
x I
n
N setting can be: 50-100-200%.
n
N can be: 50-100%.
n
N" can cause circuit-breaker damage with
n
Emax
1SDH000460R0002
, the real
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