Page 26 - Sace Emax 2 Manual for design engineers

ABB | SACE Emax 2
Neutral and frequency Adjusting of the neutral setting is used to customize the L, S and I protections on the Neutral pole with a
control factor different from the other phases.
NOTE: use the adjustment of the neutral setting only with four-pole or three-pole circuit-
breakers with external neutral: with three-pole circuit-breakers and neutral protection
active, the trip unit signals the absence of the current sensor.
The adjustment of the frequency is used in order to set the installation frequency (between 50 and 60 Hz).
Neutral parameters
The user can activate the protection and set the percentage for calculation of the protection thresholds.

Parameter Description
By setting the threshold dip-switches to the Off position, the protection on the
Enable
Neutral is disabled.
It establishes the multiplication factor applied to the trip thresholds of the
protections:
Threshold InN • 50%: trip threshold of the neutral current lower than other phases.
• 100%: same trip thresholds for all poles.
• 200%: trip threshold of the neutral current higher than other phases.

Limitations
The adjustment of the Neutral threshold to value of 200 % must be performed considering the following
formula: (I1 * InN) ≤ Iu.
I1 indicates the threshold of L protection in Amperes (example: In = 1000 A; I1 = 0.45 In = 450 A), InN is the
neutral threshold expressed as a multiplication factor (example: 2), Iu indicates the size of the circuit-breaker
(example: 1000 A).

WARNING! With 200% threshold and measured neutral current exceeding 16In, the
Trip unit resets the protection to 100% by itself

24 | © 2020 ABB | 1SDH001330R1002 - ECN000134959 - Rev. A Ekip Dip | 1 - Protections - Introduction