4.3.2.2 Consequence on accuracy for power measurement functions when
using signals from IEC 61850-9-2LE communication
The Power measurement functions (CVMMXN, CMMXU, VMMXU and VNMMXU)
contains correction factors to account for the non-linearity in the input circuits, mainly
in the input transformers, when using direct analogue connection to the IED.
The IED will use the same correction factors also when feeding the IED with analog
signals over IEC 61850-9-2LE. Since the signals via IEC 61850-9-2LE are not subject
to the same non-linearity errors this will cause an inaccuracy in the measured values.
For voltage signals the correction factors are less than 0.05% of the measured value
and no angle compensation why the impact on reported value can be ignored.
For current signals the correction factors will cause a not insignificant impact on the
reported values at low currents. The correction factors are +2.4% and -3.6 degrees at
signal levels below 5% of set base current, +0.6% and -1.12 degrees at signal level
30% of set base current and 0% and -0.44 degrees at signal levels above 100% of set
base current. Between the calibration points 5%, 30% and 100% of set base current,
linear interpolation is used. Since the output from the Power measurement function is
used as an input for the Energy measuring function (ETPMMTR) the above described
impact will also be valid for the output values for ETPMMTR.
4.3.2.3 Loss of communication
If IEC 61850-9-2LE communication is lost, protection functions in table 240are blocked:
Table 240: Blocked protection functions if IEC 61850-9-2LE communication is interrupted.
Function description
IEC 61850 identification Function description IEC 61850 identification
Broken conductor check BRCPTOC Phase preference logic PPLPHIZ
Capacitor bank
protection
CBPGAPC PoleSlip/Out-of-step
protection
PSPPPAM
Breaker failure
protection
CCRBRF Restricted earth fault
protection, low
impedance
REFPDIF
Pole discordance
protection
CCRPLD Two step residual
overvoltage protection
ROV2PTOV
Breaker failure
protection, single phase
version
CCSRBRF Rate-of-change
frequency protection
SAPFRC
Current circuit
supervison
CCSRDIF Overfrequency
protection
SAPTOF
Compensated over- and
undervoltage protection
COUVGAPC Underfrequency
protection
SAPTUF
General currrent and
voltage protection
CVGAPC Sudden change in
current variation
SCCVPTOC
Table continues on next page
1MRK504116-UUS C Section 4
Station communication
821
Application manual
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