Hitachi Relion 670 Series Applications Manual page 171

1MRK506375-UEN Rev. N
SN> is the operate power level for the directional function when OpMode is set 2I02U0Cosfi. 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:

t
inv
2
IECEQUATION16103 V1 EN-US
INDir> is the operate current level for the directional function when OpMode is set 2I0 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 22:
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
IEC Inverse
IEC Extremely Inverse
IEC Short Time Inverse
IEC Long Time Inverse
IEC Definite Time
User Programmable
ASEA RI
RXIDG (logarithmic)
See chapter "Inverse time characteristics" in Technical Manual for the description of different
characteristics
Railway application RER670
Application manual

kSN Sref


 
I 2 U cos measured
0 0
Inverse time characteristics
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
Section 8
Current protection
(Equation 56)
165