7SG11 Argus Technical Reference
©2013 Siemens Protection Devices Limited
P20007 Page 27 of 71
Ia
Ib
Ic
P300008 Protection Functions / Time Delayed P/F
1
Dir'n B Fwd
Dir'n C Fwd
Dir'n A Fwd
1
c
start
trip
c
start
trip
c
start
trip
P/F Starter
P/F Charact Inhib
P/F Charact.
*
*
*
*
*
This diagram shows the logic for overcurrent
elements in the forward direction; reverse is
similar. On relays with no directional elements
these inputs and settings are omitted.
Event
Event
Event
Event
Event
Event
Phase A starter
Phase A delayed trip
Phase B starter
Phase B delayed trip
Phase C starter
Phase C delayed trip
P/F Charact. Dir Control
P/F Charact. Setting
P/F Charact.
P/F Charact. Time Mult
P/F Charact. Delay
Relay Reset Delay
c
Figure 2.3-1
Functional Diagram – Characteristic Phase-fault Overcurrent Element
The earth-fault pole similarly has its own delayed overcurrent element with its own starter setting and selectable
IDMT/DTL characteristic.
Ie
P300008 Protection Functions / Time Delayed E/F
Dir'n E/F Fwd
c
start
trip
E/F Starter
E/F Charact Inhib
E/F Charact.
*
This diagram shows the logic for overcurrent
elements in the forward direction; reverse is
similar. On relays with no directional elements
these inputs and settings are omitted.
*
Event
Event
Earth starter
Earth delayed trip
*
E/F Charact. Dir Control
E/F Charact. Setting
E/F Charact.
E/F Charact. Time Mult
E/F Charact. Delay
Relay Reset Delay
c
Figure 2.3-2
Functional Diagram – Characteristic Earth-fault Overcurrent Element
2.3.2 Instantaneous elements
There are three separate instantaneous elements per pole: Lowset, Highset 1 and Highset 2. The setting range of
each element allows it to be set and used either as a lowset or highset protection, or for overcurrent monitoring.
For each element common settings are used by each of the three phase fault poles of the relay, each element
has an ‘OFF’ setting. Each element has a shaped instantaneous characteristic plus follower time delay which can
be used to provide time grading margins, sequence co-ordination grading, or for scheme logic. The instantaneous
elements have transient free, low overreach, operation under conditions of high values of system X/R.
Figure 2.3-2 and the following text describe the operation of the Lowset element, Highset 1 and Highset 2. Each
of these elements is identical in operation.
Each instantaneous element has its own directional control setting
Protection:
P/F Lowset Dir Control
. A current level
setting
Protection:
P/F Lowset Setting
sets the pickup level, which can be followed by a time delay,
Protection:
P/F Lowset
Delay
, the element output is mapped
O/P Relay Config.:
P/F Lowset
.