ABB REC670 Applications Manual page 206

Section 8
Current protection
200
ROADir is Relay Operating Angle. ROADir is identifying a window around the
reference direction in order to detect directionality. ROADir is set in degrees. For
angles differing more than ROADir from RCADir the function is blocked. The setting
can be used to prevent unwanted operation for non-faulted feeders, with large
capacitive ground fault current contributions, due to CT phase angle error.
INCosPhiPU is the pickup 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 pickup power level for the directional function when OpModeSel is set
3I03V0Cosfi. The setting is given in % of SBase. The setting should be based on
calculation of the active or 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. SRef is the reference residual power, given in % of SBase. TDSN is
the time multiplier. The time delay will follow the following expression:
×
TDSN Sref
=
t
inv
× × j
3I 3V cos (measured)
0 0
EQUATION2030-ANSI V1 EN-US
INDirPU is the pickup current level for the directional function when OpModeSel is set
3I0 and fi. The setting is given in % of IBase. The setting should be based on
calculation of the ground fault current at required sensitivity of the protection.
OpINNonDir is set Enabled to activate the non-directional residual current protection.
INNonDirPU is the pickup current level for the non-directional function. The setting is
given in % of IBase. This function can be used for detection and clearance of cross-
country faults in a shorter 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:
1MRK 511 401-UUS A
(Equation 59)
Bay control REC670 2.2 ANSI
Application manual