Energy Storage; Figure 6.4.7-1Energy Direction Convention - Siemens 7SR18 Solkor Manual

7SR18 Description Of Operation
6.4.7

Energy Storage

The measured Power is continuously integrated (over a one-second window) to produce 4 Energy quantities: -
·
Active Export Energy (W)
·
Active Import Energy (W)
·
Reactive Export Energy (VAr)
·
Reactive Import Energy (VAr)
The Direction of Energy transfer is set by: SYSTEM CONFIG> Export Power/Lag VAr. With both Export Power
(W) and Lag VAr (VAr) set to be +ve, the Direction of Energy transfer will follow the IEC convention, as shown in
the figure.
180°
ACTIVE ENERGY IMPORT
(watts reverse)
IEC CONVENTION : -ve watts
Setting either the Export Power (W) or Lag VAr (VAr) to be -ve, will reverse the Direction of the Energy transfer
for these quantities. So forward VAr will then be reported as Imported Reactive Energy, and forward Watts will be
reported as Exported Active Energy.
When the accumulated Energy quantities reach a set increment, the Relay issues a pulse to the binary outputs:
OUTPUT CONFIG/OUTPUT MATRIX> Active Exp Pulse, Active Imp Pulse, Reactive Exp Pulse and Reactive
Imp Pulse.
The Energy increments are set by the settings: DATA STORAGE/ENERGY STORAGE> Active Exp Energy
Unit, Active Imp Energy Unit, Reactive Exp Energy Unit and Reactive Imp Energy Unit. These setting also
define the resolution of the stored energy values reported by instruments and communications protocols. The
value is stored in the range 0-999999 which continues from zero automatically when 999999 is reached.
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REACTIVE ENERGY IMPORT
(vars reverse)
IEC CONVENTION : -ve vars
+90°
POWER FACTOR LAGGING POWER FACTOR LEADING
ACTIVE (W) IMPORT ACTIVE (W) EXPORT
REACTIVE (VAr) IMPORT REACTIVE (VAr) IMPORT
POWER FACTOR LEADING POWER FACTOR LAGGING
ACTIVE (W) IMPORT ACTIVE (W) EXPORT
REACTIVE (VAr) EXPORT REACTIVE (VAr) EXPORT
-90°
REACTIVE ENERGY EXPORT
(vars forward)
IEC CONVENTION : +ve vars
Figure 6.4.7-1 Energy Direction Convention
0°
ACTIVE ENERGY EXPORT
(watts forward)
IEC CONVENTION : +ve watts
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