ABB REG670 Applications Manual page 371

1MRK 502 071-UEN -
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual
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 earth fault current contributions, due to CT phase angle error.
INCosPhi> is the operate current level for the directional function when OpMode is
set 3I0Cosfi. The setting is given in % of IBase. The setting should be based on
calculation of the active or capacitive earth fault current at required sensitivity of the
protection.
SN> is the operate power level for the directional function when OpMode is set
3I03U0Cosfi. The setting is given in % of SBase. The setting should be based on
calculation of the active or capacitive earth 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. kSN is
the time multiplier. The time delay will follow the following expression:
×
kSN Sref
=
t
inv j
× ×
3I 3U cos (measured)
0 0
EQUATION1957 V1 EN
INDir> is the operate current level for the directional function when OpMode is set
3I0 and fi. The setting is given in % of IBase. The setting should be based on
calculation of the earth fault current at required sensitivity of the protection.
OpINNonDir> is set On to activate the non-directional residual current protection.
INNonDir> is the operate 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:
Table 39: Inverse time characteristics
Curve name
ANSI Extremely Inverse
ANSI Very Inverse
ANSI Normal Inverse
Table continues on next page
Section 9
Current protection
(Equation 208)
365