7SR11 & 7SR12 Applications Guide
©2017 Siemens Protection Devices Limited Chapter 7 Page 5 of 48
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)
Figure 1.5-1 Example Use of Alternative Settings Groups
RADIAL SUBSTATION
Start
generators
Select alternate
settings group
Local
Generation
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
Non-essential
loads
Trip non-essential loads
To Next Page
Loading...
Need help?
General
