ABB Relion 670 Series Applications Manual page 316

Section 14
Secondary system supervision
In this function, a current based delta supervision is implemented in a phase segregated
design. The delta function has the following features:
• Instantaneous sample based delta detection (vectorial delta)
• True RMS value based delta detection
• DFT magnitude based delta detection
•
nd
2
•
rd
3
Instantaneous sample based delta supervision is very fast; the delta is detected in less than a
cycle typically. This mode can be used for high impedance earth fault detection. All the other
supervision modes like RMS/DFT Mag requires minimum one cycle for delta detection.
Therefore, the choice of delta detection mode should be based on the application
requirement. Instantaneous sample based delta supervision can be used for functions that are
used as protection enabler or fault detector. For time delayed functions, other modes can be
used. Current based function can be used for load supervision also in DFT Mag based delta
mode.
14.5.3 Setting guidelines
Operation : This setting is used to enable/disable the delta supervision function.
Imin : The minimum start level setting should be set as % of IBase . This setting enables the
function to start detecting delta. Typical setting is 10% of
MeasMode : This setting is used to detect the mode of measurement; phase to phase or phase
to ground .
OpMode : This setting is used to select the mode of operation. For protection applications, this
should be set to
DelI> : This setting is used to detect the start value for instantaneous sample, RMS, DFT mag
based delta detection. Set a typical value of 200% of
detection.
DeltaT : This setting defines the number of old cycles data to be used for delta calculation in
RMS/DFT Mag mode. Typical value is 2 cycles.
tHold : This setting defines the pulse length for supervision start signal. Typical value is 100 ms.
EnaHarm2Blk : This setting should be set to ON, to enable blocking for heavy inrush currents or
other sources of 2
Harm2BlkLev : This is the blocking level of 2
Typical setting is 15% of fundamental signal.
EnStValAdap : This setting should be set to ENABLE in special networks where settings in the
network are adapted with respect to 3
Harm3Level : This is the set level of 3
DelI> should be modified. Typical setting is 15% of fundamental signal.
the
StValGrad : This setting is used to modify the DelI> based on 3
is 10% to modify the
310
harmonic blocking of delta function
harmonic based adaption of starting value
Instantaneous 1 cycle old . Load supervision can be done using DFT mag mode.
nd
harmonic injections.
DelI> .
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IBase .
IBase to use this function as fault
nd
harmonic with respect to the fundamental signal.
rd
harmonic level.
rd
harmonic with respect to fundamental signal at which
1MRK 511 401-UEN Rev. K
GUID-69D28046-FAC4-4EF3-9886-F7B0F6341196 v2
rd
harmonic level. Typical setting
Bay control REC670
Application manual