Measurement Function Applications - ABB REF615 Applications Manual

1MRS756378 D
9.1.9
REF615
Application Manual
The three-phase voltage measurement function, VMMXU, is used for monitoring and
metering the phase-to-phase voltages of the power system. The phase-to-earth
voltages are also available in VMMXU.
The residual current measurement function, RESCMMXU, is used for monitoring
and metering the residual current of the power system.
The residual voltage measurement function, RESVMMXU, is used for monitoring
and metering the residual voltage of the power system.
The sequence current measurement, CSMSQI, is used for monitoring and metering
the phase sequence currents.
The sequence voltage measurement, VSMSQI, is used for monitoring and metering
the phase sequence voltages.
The three-phase power and energy measurement PEMMXU is used for monitoring
and metering the active power P, reactive power Q, apparent power S, power factor
PF and for calculating the accumulated energy separately as forward active, reverse
active, forward reactive and reverse reactive. PEMMXU calculates these quantities
with the fundamental frequency phasors, that is, the DFT values of the measured
phase current and phase voltage signals.
The information of the measured quantity is available for the operator both locally in
LHMI and remotely to a network control center with communication.

Measurement function applications

The measurement functions are used for power system measurement, supervision and
reporting to LHMI, a monitoring tool within PCM600, or to the station level, for
example, with IEC 61850. The possibility to continuously monitor the measured
values of active power, reactive power, currents, voltages, power factors and so on,
is vital for efficient production, transmission, and distribution of electrical energy. It
provides a fast and easy overview of the present status of the power system to the
system operator. Additionally, it can be used during testing and commissioning of
protection and control IEDs to verify the proper operation and connection of
instrument transformers, that is, the current transformers (CTs) and voltage
transformers (VTs). The proper operation of the IED analog measurement chain can
be verified during normal service by a periodic comparison of the measured value
from the IED to other independent meters.
When the zero signal is measured, the noise in the input signal can still produce small
measurement values. The zero point clamping function can be used to ignore the noise
in the input signal and, hence, prevent the noise to be shown in the user display. The
zero clamping is done for the measured analog signals and angle values.
The demand values are used to neglect sudden changes in the measured analog signals
when monitoring long time values for the input signal. The demand values are linear
average values of the measured signal over a settable demand interval. The demand
values are calculated for the measured analog three-phase current signals.
Section 9
Measurement functions
207