Application And Setting Notes; Settings Menu - Siemens 7SR51 Device Manual

Protection and Automation Functions
5.12 50AFD Arc Flash Detection

Application and Setting Notes

5.12.4
Parameter: 50AFD-n > Setting
•
Default setting: 2 x I
This setting defines the operating current threshold of the element. The applied phase current must
exceed this setting.
This setting is used to verify that the arc detection is also accompanied by an overcurrent and so provides
a check and increases operational security. This setting should be above load current levels.
Parameter: 50GAFD-n > Setting
•
Default setting: 2 x I
This setting defines the operating current threshold of the element. The applied phase current must
exceed this setting.
This setting is used to verify that the arc detection is also accompanied by earth fault current and so
provides a check and increases operational security.
Settings Example
There should be little or no current flowing to earth in a healthy system so earth fault relays can be given far
lower pickup levels than relays which detect excess current above load current in each phase conductor. Earth
fault relays are important where the fault path to earth is a high-resistance one (such as in highly arid areas) or
where the system uses high values of earthing resistor/reactance as any earth fault current that flows in the
phase conductors will be limited.

Settings Menu

5.12.5
Functions > Function Config
Parameter
50AFD Arc Flash
Functions > Protection > 50AFD > Gn 50AFD-n
Parameter
Element
Setting
Functions > Protection > 50AFD > Gn 50GAFD-n
Parameter
Element
Setting
218
(2 ⋅ I )
n rated
(2 ⋅ I )
n rated
Range
Enabled
Disabled
Range
Enabled
Disabled
0.5 to 20 I , Δ 0.1 I
rated
Range
Enabled
Disabled
0.05 to 8 I , Δ 0.01 I
rated
Default Gn1
Disabled
Default Gn1
Disabled
2x
rated
Default Gn1
Disabled
2x
rated
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019
Settings
Gn2 Gn3 Gn4
Settings
Gn2 Gn3 Gn4
Settings
Gn2 Gn3 Gn4