ABB RELION 670 Series Technical Manual page 1045

1MRK 502 066-UUS B
ANSI05000373 V2 EN-US
Figure 540: Internal IED directionality convention for P & Q measurements
Practically, it means that active and reactive power will have positive values when they flow from
the busbar towards the protected object and they will have negative values when they flow from
the protected object towards the busbar.
In some application, for example, when power is measured on the secondary side of the power
transformer it might be desirable, from the end client point of view, to have actually opposite
directional convention for active and reactive power measurements. This can be easily achieved by
setting parameter
reactive power will have positive values when they flow from the protected object towards the
busbar.
Frequency
Frequency is actually not calculated within measurement block. It is simply obtained from the pre-
processing block and then just given out from the measurement block as an output.
16.1.7.3 Phase current measurement CMMXU
The Phase current measurement (CMMXU) function must be connected to three-phase current
input in the configuration tool to be operable. Currents handled in the function can be calibrated
to get better then class 0.5 measuring accuracy for internal use, on the outputs and IEC 61850.
This is achieved by magnitude and angle compensation at 5, 30 and 100% of rated current. The
compensation below 5% and above 100% is constant and linear in between, see figure 539.
Phase currents (magnitude and angle) are available on the outputs and each magnitude output
has a corresponding supervision level output (Ix_RANGE). The supervision output signal is an
integer in the interval 0-4, see section
16.1.7.4 Phase-phase and phase-neutral voltage measurements VMMXU, VNMMXU
The voltage function must be connected to three-phase voltage input in the configuration tool to
be operable. Voltages are handled in the same way as currents when it comes to class 0.5
calibrations, see above.
Technical manual
Busbar
52
P Q
Protected
Object
ANSI05000373_2_en.vsd
PowAngComp to value of 180.0 degrees. With such setting the active and
IED
"Measurement supervision".
Section 16
Monitoring
SEMOD54417-261 v2
SEMOD54417-264 v6
SEMOD54417-268 v5
1039