ABB RELION REX640, Техническое руководство, Страница: 916 / 1960

T = Roundup
Time interval in seconds
refresh
200






(Equation 255)
The function Roundup rounds up the result to the next higher time multiple of 0.2 s
because the result of the division is not a multiple of 0.2 s in case of an odd
Time
interval setting (1, 3, 5…120 mins).
U
N
U i
Refresh
cycles
i
N
=
( )
=
∑
1
10 12
1
2
/
(Equation 256)
N Number of values to be aggregated as defined by
Equation 257
N
T
refresh
= 





0 2 .
(Equation 257)
Calculation of RMS average voltage
The RMS average voltage is calculated by aggregating the RMS U
refresh
voltage over a
time period equal to the Time interval.
U
M
U i
Average
i
M
=
( )
=
∑
1
1
2
Refresh
(Equation 258)
M Number of values to be aggregated as defined by
Equation 259
M = Round
Time interval in seconds
T
Refresh






(Equation 259)
At the initialization of the function, the average voltage is calculated considering
initial values as zero. On the IEC 61850 mapped data, the quality of the calculated
average voltage value is indicated as “Questionable” until the first complete
time interval passes. The calculated average voltage measurement for the set
Time interval for all three phase-to-earth and phase-to-phase voltages U_MEAN_A,
U_MEAN_B, U_MEAN_C, U_MEAN_AB, U_MEAN_BC and U_MEAN_CA is available in
the Monitored data view.
The calculated average voltage can be reset by the
RESET
binary input. The
calculated average voltage can also be reset using PHVPTOV1 Reset mean on the
Clear menu.
When the
INITIALIZE
input is activated, the average voltage measurement value is
initialized with the 10/12-cycle RMS voltage. The average voltage measurement value
can also be initialized using PHVPTOV1 Ini mean on the Clear menu.
Protection functions 1MRS759142 F
916 REX640
Technical Manual