2ndHarmStab
: The rate of 2nd harmonic current content for activation of the 2nd
harmonic restrain signal. The setting is given in % of the fundamental frequency
residual current.
8.5
Sensitive directional residual overcurrent and power
protection SDEPSDE
SEMOD171436-1 v4
8.5.1
Identification
SEMOD172025-2 v4
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Sensitive directional residual over
current and power protection
SDEPSDE
IN>
IEC15000260 V1 EN-US
67N
8.5.2
Application
SEMOD171959-4 v12
In networks with high impedance earthing, the phase-to-earth fault current is
significantly smaller than the short circuit currents. Another difficulty for earth
fault protection is that the magnitude of the phase-to-earth fault current is almost
independent of the fault location in the network.
Directional residual current can be used to detect and give selective trip of phase-
to-earth faults in high impedance earthed networks. The protection uses the
residual current component 2I
0
· cos φ, where φ is the angle between the residual
current and the residual voltage (-2U
0
), compensated with a characteristic angle.
Alternatively, the function can be set to strict 2I
0
level with a check of angle φ.
Directional residual power can also be used to detect and give selective trip of
phase-to-earth faults in high impedance earthed networks. The protection uses the
residual power component 2I
0
· 2U
0
· cos φ, where φ is the angle between the
residual current and the reference residual voltage, compensated with a
characteristic angle.
A normal non-directional residual current function can also be used with definite or
inverse time delay.
A backup neutral point voltage function is also available for non-directional
residual overvoltage protection.
In an isolated network, that is, the network is only coupled to earth via the
capacitances between the phase conductors and earth, the residual current always
Section 8
1MRK 506 375-UEN A
Current protection
174
Railway application RER670 2.2 IEC
Application manual
Summary of Contents for RELION RER670
Page 1: ...RELION 670 SERIES Railway application RER670 Version 2 2 IEC Application manual ...
Page 2: ......
Page 22: ...16 ...
Page 48: ...42 ...
Page 70: ...64 ...
Page 80: ...74 ...
Page 100: ...94 ...
Page 210: ...204 ...
Page 364: ...358 ...
Page 384: ...378 ...
Page 468: ...462 ...
Page 494: ...488 ...
Page 504: ...498 ...
Page 505: ...499 ...