Demand - Siemens 7SR242 Manual

5.5

Demand

Maximum, minimum and mean values of line currents and voltage (where applicable) are available as instruments
which can be read in the relay INSTRUMENTS MENU or via Reydisp.
The DATA STORAGE > DEMAND DATA LOG > Data Log Period setting is used to define the time/duration
after which the instrument is updated. The updated value indicates the maximum, minimum and mean values for
the defined period.
The Gn Demand Window setting defines the maximum period of time over which the demand values are valid. A
new set of demand values is established after expiry of the set time.
The Gn Demand Window Type can be set to FIXED, PEAK or ROLLING.
When set to FIXED the maximum, minimum and mean values demand statistics are calculated over
fixed Window
are reset and a new window is started.
When set to PEAK the maximum and minimum values within the Demand Window time setting is
recorded.
When set to ROLLING the maximum, minimum and mean values demand statistics are calculated over
a moving Window duration. The internal statistics
are updated when the window advances every Updated Period.
The statistics can be reset from a binary input or communication command, after a reset the update period and
window are immediately restarted.
©2010 Siemens Protection Devices Limited
duration. At the end
7SR242 Duobias Description Of Operation
of each window the
Chapter 1 Page 47 of 52
internal statistics