ABB 615 Series ANSI, Technical Manual

Page: 551 / 713

Section 8
1MAC050144-MB C
Measurement functions
544 615 series ANSI
Technical Manual
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.
The limit supervision indicates, if the measured signal exceeds or goes below the set limits.
Depending on the measured signal type, up to two high limits and up to two low limits can
be set for the limit supervision.
The deadband supervision reports a new measurement value if the input signal has gone
out of the deadband state. The deadband supervision can be used in value reporting
between the measurement point and operation control. When the deadband supervision is
properly configured, it helps in keeping the communication load in minimum and yet
measurement values are reported frequently enough.
8.2 Three-phase current measurement, IA, IB, IC
8.2.0.1 Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Three-phase current CMMXU 3I IA, IB, IC