Zero Clamping - ABB REC670 Applications Manual

1MRK 511 401-UEN A
17.1.3
Bay control REC670 2.2 IEC
Application manual
It is possible to calibrate the measuring function above to get better then class 0.5
presentation. This is accomplished by angle and amplitude compensation at 5, 30
and 100% of rated current and at 100% of rated voltage.
The power system quantities provided, depends on the actual
hardware, (TRM) and the logic configuration made in PCM600.
The measuring functions CMSQI and VMSQI provide sequence component
quantities:
• I: sequence currents (positive, zero, negative sequence, amplitude and angle)
• U: sequence voltages (positive, zero and negative sequence, amplitude and
angle).

Zero clamping

Measuring functions CVMMXN, CMMXU, VMMXU and VNMMXU have no
interconnections regarding any settings or parameters.
Zero clampings are also handled entirely by ZeroDb separately for each function's
every output signal. For example, zero clamping of U12 is handled by
UL12ZeroDb in VMMXU, zero clamping of I1 is handled by IL1ZeroDb in
CMMXU, and so on.
Example of CVMMXN operation
Outputs seen on the local HMI under Main menu/Measurements/Monitoring/
Servicevalues(P_Q)/CVMMXN(P_Q):
S Apparent three-phase power
P Active three-phase power
Q Reactive three-phase power
PF Power factor
ILAG I lagging U
ILEAD I leading U
U System mean voltage, calculated according to selected mode
I System mean current, calculated according to selected mode
F Frequency
Relevant settings and their values on the local HMI under Main menu/
Settings/IED settings/Monitoring/Servicevalues(P_Q)/CVMMXN(P_Q):
Section 17
Monitoring
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