7SG164 Ohmega 400 Series Description of Operation
5 Multiple Setting Groups
The relays provides up to eight alternative settings groups, making it possible to edit one group while the
relay protection algorithms operate using another ‘active’ group. The relay can be switched from one group
of settings to another to suit alterations in the power system configuration. The process of changing the
settings takes place changed sequentially, and may take up to 2s to update all the settings, during which
time the relay remains operative.
A change of group can be achieved either locally at the relay fascia, remotely via a communications
interface command or automatically by the energising of a status input. In the case of the last method, the
‘Status Configuration’/‘Settings Group Select’ setting is used to configure any one (or more) of the status
inputs to select a settings group. The selected group is then made active if the status input is energised and
remains active for as long as the input remains energised. When the input is de-energised the relay returns
to the original settings group.
All Settings are stored in non-volatile memory.
6 Instrumentation And Metering
6.1 Metering
The metering features provide continuous data accessed either from the relay fascia in “
Instruments
Display Mode
” or via the data communications interface. While in the display mode pressing the
Ø
key
accesses the following metering data:
6.2 Secondary Values
RMS values for the secondary I
A
, I
B
, I
C
, V
A
, V
B
, V
C
values measured by the relay.
6.3 Primary Values
RMS values for the primary I
A
, I
B
, I
C
, V
A
, V
B
, V
C
values on the system.
6.4 Phase Sequence Currents and Voltages
RMS value for the secondary phase sequence quantities measured by the relay. Positive, negative and zero
sequence current and voltage are all measured.
6.5 Watts
Three phase exported primary power.
6.6 VArs
Three phase exported primary VArs.
6.7 Power Factor
Cosine of
φ
measured on phase A.
6.8 Load Direction
Forward, Reverse on each phase.
Indications showing the condition of the status input signals and the output contacts are available. Where the
display indicates a
I
then that position is shown to be active.
©2011 Siemens Protection Devices Limited
Chapter 1 Page 4 of 12
