Siemens 7SR51 - Application and Setting Notes; Settings Menu

Application and Setting Notes
Parameter: 50AFD-n > Setting
•
Default setting: 2 x I
n
(2 ⋅ I
rated
)
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
n
(2 ⋅ I
rated
)
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
Functions > Function Config
Parameter Range Settings
Default Gn1 Gn2 Gn3 Gn4
50AFD Arc Flash Enabled
Disabled
Disabled
Functions > Protection > 50AFD > Gn 50AFD-n
Parameter Range Settings
Default Gn1 Gn2 Gn3 Gn4
Element Enabled
Disabled
Disabled
Setting 0.5 to 20 I
rated
, Δ 0.1 I
rated
2x
Functions > Protection > 50AFD > Gn 50GAFD-n
Parameter Range Settings
Default Gn1 Gn2 Gn3 Gn4
Element Enabled
Disabled
Disabled
Setting 0.05 to 8 I
rated
, Δ 0.01 I
rated
2x
5.12.4
5.12.5
Protection and Automation Functions
5.12 50AFD Arc Flash Detection
218 Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019