Measurements Cvmmxn - Hitachi Relion 650 Series Technical Manual

Section 12
Monitoring
Integral dead-band reporting
The measured value is reported if the time integral of all changes exceeds the pre-set limit
(XDbRepInt),
shown. The picture is simplified: the process is not continuous but the values are evaluated with a
time interval of one execution cycle from each other.
The last value reported, Y1 in
difference is calculated between the last reported and the newly measured value and is multiplied by
the time increment (discrete integral). The absolute values of these integral values are added until
the pre-set value is exceeded. This occurs with the value Y2 that is reported and set as a new base
for the following measurements (as well as for the values Y3, Y4 and Y5).
The integral dead-band supervision is particularly suitable for monitoring signals with small variations
that can last for relatively long periods.
Y
A >=
pre-set value
Value Reported
(1st)
D0E12012T201305151403 V1 EN-US
Figure 91: Reporting with integral dead-band supervision
12.1.8.2

Measurements CVMMXN

Mode of operation
The measurement function must be connected to three-phase current and three-phase voltage input
in the configuration tool (group signals), but it is capable to measure and calculate above mentioned
quantities in nine different ways depending on the available VT inputs connected to the IED. The end
user can freely select by a parameter setting, which one of the nine available measuring modes shall
be used within the function. Available options are summarized in the following table:
172
Figure 91, where an example of reporting with integral dead-band supervision is
Figure 91
A1 >=
pre-set value
Y2 A1
Value
A
Reported
Y1
© 2021 Hitachi Energy. All rights reserved.
serves as a basic value for further measurement. A
A2 >=
pre-set value
Y3
A2
Y4
Value
Reported
Value
Reported
1MRK 511 557-UEN Rev. A
D0E6136T201305151403 v1
A3 + A4 + A5 + A6 + A7 >=
pre-set value
A4
A6
A5
A7
A3
Y5
Value
Reported
99000530.vsd
D0E6143T201305151403 v1
Technical Manual
t