ABB RELION 670 Series Applications Manual page 140

Section 8
Current protection
RCADir the function is blocked. The setting can be used to prevent unwanted operation for
from
non-faulted feeders, with large capacitive ground fault current contributions, due to CT phase
angle error.
INCosPhiPU is the operate current level for the directional function when OpModeSel is set
3I0Cosfi . The setting is given in % of IBase . The setting should be based on calculation of the
active or capacitive ground fault current at required sensitivity of the protection.
SN_PU is the operate power level for the directional function when OpModeSel is set 3I03V0Cosfi .
The setting is given in % of
capacitive ground fault residual power at required sensitivity of the protection.
The input transformer for the Sensitive directional residual over current and power protection
function has the same short circuit capacity as the phase current transformers. Hence, there is no
specific requirement for the external CT core, i.e. any CT core can be used.
If the time delay for residual power is chosen the delay time is dependent on two setting
parameters.
The time delay will follow the following expression:
=
t
inv
3I 3V cos (measured)
EQUATION2030-ANSI V1 EN-US
INDirPU is the operate current level for the directional function when OpModeSel is set 3I0 and fi .
The setting is given in % of
current at required sensitivity of the protection.
OpINNonDir is set Enabled to activate the non-directional residual current protection.
INNonDirPU is the operate current level for the non-directional function. The setting is given in %
IBase . This function can be used for detection and clearance of cross-country faults in a shorter
of
time than for the directional function. The current setting should be larger than the maximum
single-phase residual current on the protected line.
TimeChar is the selection of time delay characteristic for the non-directional residual current
protection. Definite time delay and different types of inverse time characteristics are available:
Table 17:
Curve name
ANSI Extremely Inverse
ANSI Very Inverse
ANSI Normal Inverse
ANSI Moderately Inverse
ANSI/IEEE Definite time
ANSI Long Time Extremely Inverse
ANSI Long Time Very Inverse
ANSI Long Time Inverse
IEC Normal Inverse
IEC Very Inverse
Table continues on next page
134
SBase . The setting should be based on calculation of the active or
SRef is the reference residual power, given in % of SBase . TDSN is the time multiplier.
×
TDSN Sref
× × j
0 0
IBase . The setting should be based on calculation of the ground fault
Inverse time characteristics
1MRK 511 364-UUS A
(Equation 52)
Application manual