Figure 6-1 Energy Direction Convention - Siemens 7SR17 Rho Manual

6.4 I
NSTRUMENTS
Real-time data is available from the relay fascia in the 'Instruments Mode' or via the data communications
interface.
The Primary values are calculated using the VT ratios set in the CT/VT Config menu.
The user can add the meters that are most commonly viewed to a 'Favourites' window by pressing 'ENTER' key
when viewing a meter.
Config/Favourite Meters Timer menu.
For a detailed description refer to Technical Manual Section 2 – Settings and Instruments.
6.4.1 Energy - 7SR1705/6
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 e.g. an
induction motor consumes Watts and VArs, this is shown in Figure 6-1 as positive Watts and positive VArs.
GENERATOR CIRCUIT
I
ACTIVE ENERGY IMPORT
(watts reverse)
IEC CONVENTION : -ve watts
I
©2014 Siemens Protection Devices Limited
The relay will scroll through these meters at an interval set in the System
Direction of load
REACTIVE ENERGY IMPORT (VArs reverse)
IEC CONVENTION :
V
POWER FACTOR LAGGING
ACTIVE (W) IMPORT
REACTIVE (VAr) IMPORT
180°
POWER FACTOR LEADING
ACTIVE (W) IMPORT
REACTIVE (VAr) EXPORT
V
REACTIVE ENERGY EXPORT (vArs forward)
IEC CONVENTION :
Figure 6-1 Energy Direction Convention
Chapter 1) 7SR17 Rho Description Of Operation
power flow
M
-ve vars
+90°
POWER FACTOR LEADING
ACTIVE (W) EXPORT
REACTIVE (VAr) IMPORT
POWER FACTOR LAGGING
ACTIVE (W) EXPORT
REACTIVE (VAr) EXPORT
-90°
+ve vars
I
V
ACTIVE ENERGY EXPORT
0°
(watts forward)
IEC CONVENTION :
watts
V
I
INDUCTION
MOTOR CIRCUIT
Page 73 of 78
+ve