Download 3 - Schneider Electric

Metering functions
Residual voltage
Neutral point voltage
Residual voltage
Operation
This function gives the following values:
b main residual voltage V0 = V1 + V2 + V3
b additional residual voltageV ′ 0 = V ′ 1 + V ′ 2 + V ′ 3
2
The residual voltage value may be:
b calculated by an open star/delta VT
b or calculated by taking the internal sum of the 3 phase voltages.
It is based on the measurement of the fundamental 50 Hz or 60 Hz component
of the voltages.
Readout
The measurements may be accessed via:
b the Sepam display via the
key
b the display of a PC with the SFT2841 software
b the communication link.
Characteristics
0.015 to 3 Vnp (1)
V or kV
1V
±1 % from 0.5 to 3 Vnp
±2 % from 0.05 to 0.5 Vnp
±5 % from 0.02 to 0.05 Vnp
Display format
3 significant digits
Refresh interval
1 second (typical)
(1) Vnp: primary rated phase-to-neutral voltage (Vnp = Unp/3).
Measurement range
Units
Resolution
Accuracy
Neutral point voltage
Operation
This function gives the value of the zero sequence voltage Vnt, measured at the
neutral point of a generator or motor by a dedicated VT:
Vnt = ( V1 + V2 + V3 ) ⁄ 3
Readout
The measurements may be accessed via:
b the Sepam display via the
key
b the display of a PC with the SFT2841 software
b the communication link.
Characteristics
0.015 Vnp to 3 Vntp (1)
V or kV
1V
±1 % from 0.5 to 3 Vntp
±2 % from 0.05 to 0.5 Vntp
±5 % from 0.02 to 0.05 Vntp
Display format
3 significant digits
Refresh interval
1 second (typical)
(1) Vntp: neutral point voltage transformer primary voltage.
Measurement range
Units
Resolution
Accuracy
SEPED303001EN - 01/2013
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