External Toroid Protections; Presentation; Gext Protection - ABB SACE Emax E1.2 Operating Instructions For The Design Engineer

14 - External toroid protections

Presentation The presence of SGR external toroids and Rc allows the use of Gext and Rc protections respectively.

Gext Protection

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101 | © 2017 ABB | 1SDH001330R0002 - ECN000058721 Rev. A
External toroids can be connected to all versions of the protection trip units of the Touch range.
NOTE: the Rc protection RC requires the presence of an Rc Rating Plug and an Ekip Measuring
Pro module.
List of protections
Symbol
Gext
Rc
Operating principle
The protections have a series of parameters available allowing the user to adjust the activation thresholds and
the opening times of the circuit-breaker.
The operating principle of all the protections is similar: if the current exceeds the protection threshold that has
been set, the specific protection enters the alarm condition and starts timing.
The duration of the delay depends on the threshold and time parameters set, and two cases can be
distinguished according to the dynamics of the current:
• If the alarm condition persists, the trip unit opens the circuit-breaker.
• If the current drops below the protection threshold, the trip unit exits from the alarm condition, interrupts
the delay and does not make the circuit-breaker open.
For the Gext protection the protection threshold is related to the size of the current of the of the SGR external
toroid and, for the Rc protection, to of preset current values.
IMPORTANT:
• To manage the circuit-breaker tripping with a specific protection, the protection itself
must be enabled and, if supported, must have the Trip Enable parameter activated.
• All the protections have a default configuration: in the event of activation, check the
parameters and make changes according to the requirements of your installation.
Path
Main page - Menus - Settings - Circuit Breaker - Ground protection (enabling the presence of the external
toroid)
Main page - Menus - Protections (protection parameters)
ext
NOTE: the menu containing the Gext protection parameters is activated if the presence of
the SGR external toroid was previously enabled in the appropriate menu.
Function
Gext protection protects against external earth faults, detecting the fault current with the appropriate SGR
external toroid
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NOTE:
• The protection is available for LSIG version protection trip units.
• For the Gext protection to function correctly also in conditions of low installation currents, it is
recommended to connect the protection trip unit to an auxiliary power supply.
When the activation threshold is exceeded, the protection trips within a fixed or dynamic time (the time
decreases as the current reading increases).
Protection against
Earth fault on external toroid with adjustable delay
Residual current
Continued on the next page
Ekip Touch protection trip unit | 14 - External toroid protections
ABB | SACE Emax 2