Section 1: Common Functions; Multiple Settings Groups - Siemens 7SR224 Technical Manual

Section 1: Common Functions

1.1

Multiple Settings Groups

Alternate settings groups can be used to reconfigure the relay during significant changes to system conditions
e.g.
Primary plant switching in/out.
Summer/winter or day/night settings.
switchable earthing connections.
Loss of Grid connection (see below)
Industrial system draws power from grid
system during normal operation
Relays normally use settings group 1
On loss of mains:
Local generation switched in.
Non essential loads tripped
Relays on essential circuits switched to
settings group 2 to reflect new load and
fault currents
Figure 1.1-1 Example Use of Alternative Settings Groups
©2010 Siemens Protection Devices Limited
Start
generators
Local
Generation
Non-essential
loads
7SR224 Argus Applications
Trip non-essential loads
Select alternate
settings group
RADIAL SUBSTATION
Chapter 7 Page 4 of 50