7PG2113/4/5/6 Solkor Description of Operation
6.6
2nd Harmonic Block/Inrush Restraint (81HBL2) phase
elements only
Inrush restraint detector elements are provided, these monitor the line currents.
The inrush restraint detector can be used to block the operation of selected elements during transformer
magnetising inrush conditions.
The
81HBL2 Bias
setting allows the user to select between
Phase
,
Sum
and
Cross
methods of measurement:
Phase
Each phase is inhibited separately.
Sum
With this method the square root of the sum of the squares of the second harmonic in each
phase is compared to each operate current individually.
Cross
All phases are inhibited when any phase detects an inrush condition.
An output is given where the measured value of the second harmonic component is above the
81HBL2
setting.
IL1
IL2
IL3
L2 81HBL2
c
L1 81HBL2
L3 81HBL2
81HBL2
> 1
Figure 6.6-1 Functional Diagram for Harmonic Block Feature (81HBL2)
6.7
Demand
Maximum, minimum and mean values of line currents, voltages and power (where applicable) are available as
instruments which can be read in the relay INSTRUMENTS MENU or via Reydisp.
The
Gn Demand Log Time Sync
when set as
ENABLED
configures the Demand Log Update Period (see
below) equal to the
DATA STORAGE > Data Log Period
setting.
The
Gn Demand Log Update 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. Note that
this setting can be over-ridden by the
Gn Demand Log Time Sync
setting.
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
or
PEAK
or
ROLLING
.
When set to
FIXED
the maximum, minimum and mean values demand statistics are calculated over
fixed Window duration. At the end of each window the internal statistics
are reset and a new window is started.
When set to
PEAK
the maximum and minimum values since the feature was reset are 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 Chapter 1 Page 76 of 80