ABB Relion 670 Series Applications Manual page 424

Section 16
Monitoring
transformers (CTs and VTs). During normal service by periodic comparison of the measured value
from the IED with other independent meters the proper operation of the IED analog measurement
chain can be verified. Finally, it can be used to verify proper direction orientation for distance or
directional overcurrent protection function.
All measured values can be supervised with four settable limits that is, low-low limit, low limit, high
limit and high-high limit. A zero clamping reduction is also supported, that is, the measured value
below a settable limit is forced to zero which reduces the impact of noise in the inputs.
Dead-band supervision can be used to report measured signal value to station level when change
in measured value is above set threshold limit or time integral of all changes since the last time
value updating exceeds the threshold limit. Measure value can also be based on periodic reporting.
Main menu/Measurement/Monitoring/Service values/CVMMXN
The measurement function, CVMMXN, provides the following power system quantities:
• P, Q and S: three phase active, reactive and apparent power
• PF: power factor
• V: phase-to-phase voltage magnitude
• I: phase current magnitude
• F: power system frequency
,
The measuring functions CMMXU, VMMXU and VNMMXU provide physical quantities:
• I: phase currents (magnitude and angle) (CMMXU)
• V: voltages (phase-to-ground and phase-to-phase voltage, magnitude and angle) (VMMXU,
VNMMXU)
The CVMMXN function calculates three-phase power quantities by using fundamental frequency
phasors (DFT values) of the measured current respectively voltage signals. The measured power
quantities are available either, as instantaneously calculated quantities or, averaged values over a
period of time (low pass filtered) depending on the selected settings.
It is possible to calibrate the measuring function above to get better then class 0.5 presentation.
This is accomplished by angle and magnitude compensation at 5, 30 and 100% of rated current
and at 100% of rated voltage.
The measuring functions CMSQI and VMSQI provide sequence component quantities:
• I: sequence currents (positive, zero, negative sequence, magnitude and angle)
• V: sequence voltages (positive, zero and negative sequence, magnitude and angle).
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The available measured values of an IED are depending on the actual hardware
(TRM) and the logic configuration made in PCM600.
The power system quantities provided, depends on the actual hardware, (TRM) and
the logic configuration made in PCM600.
1MRK 511 358-UUS A
Application manual