ABB Relion 650 Series Technical Manual page 409

1MRK 506 326-UUS B
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. There are
no interconnections regarding any settings or parameters, neither between functions nor between
signals within each function.
Zero clampings are handled by
example, the zero clamping of U12 is handled by
handled by
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.
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 output values are displayed in the local HMI under Main menu/Tests/Function status/
Monitoring/CVMMXN/Outputs
The measuring functions CMMXU, VNMMXU and VMMXU 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)
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 sequential quantities:
• I: sequence currents (positive, zero, negative sequence, magnitude and angle)
• V: sequence voltages (positive, zero and negative sequence, magnitude and angle).
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
Line distance protection REL650
Technical manual
The available measured values of an IED are depending on the actual hardware
(TRM) and the logic configuration made in PCM600.
ZeroDb for each signal separately for each of the functions. For
ILZeroDb in CMMXU.
The power system quantities provided, depends on the actual hardware, (TRM) and
the logic configuration made in PCM600.
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VLZeroDB in VMMXU, zero clamping of I1 is
Section 13
Monitoring
403