ABB RELION REX640 Technical Manual page 839

1MRS759142 C
REX640
Technical Manual
The RMS refresh voltage is calculated by aggregating the U
voltage over a time period of T
Time interval.
Time interval in seconds

T = Roundup
refresh


GUID-2224EC5D-EAB2-4A16-A67D-5D3BE90EF161 V1 EN
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).
N
1
U U
Refresh
=
∑
10 12 / cycles
N
i 1
=
GUID-8045FB58-0B8A-4786-8A8C-95F31676F7F1 V1 EN
N Number of values to be aggregated as defined by
T
refresh
 
N
=
 
0 2 .
 
GUID-19A34FB7-4312-49BB-AFA5-D6B0BCEE3A03 V1 EN
Calculation of RMS average voltage
The RMS average voltage is calculated by aggregating the RMS U
a time period equal to the Time interval.
2
M
1
U U
Average =
∑
Refresh
M
i
1
=
GUID-7EC5C81C-39F4-404C-812F-61ECEA4EEE93 V1 EN
M Number of values to be aggregated as defined by
Time interval in seconds

M = Round

T

GUID-F24C98C0-0969-4A37-9635-747629FD9D90 V1 EN
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 time period T
refresh


200

2
i
( )
Equation 211
i
( )
Equation 213


Refresh

Section 4
Protection functions
/ U RMS
10cycles 12cycles
depends on the setting
refresh
(Equation 209)
(Equation 210)
(Equation 211)
voltage over
Refresh
(Equation 212)
(Equation 213)
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