ABB 615 series Technical Manual page 421

1MAC059074-MB A
615 series ANSI
Technical Manual
The polarity of the polarizing quantity can be changed (rotated by 180°)
by setting Pol reversal to "True" or by switching the polarity of the
residual voltage measurement wires.
Residual power calculation
The Residual power calculation module calculates the magnitude of residual power
3VGIGCosφ. Angle φ is the angle between the operating quantity and polarizing quantity,
compensated with a characteristic angle. The angle value is received from the Directional
calculation module. The Directional calculation module enables the residual power
calculation only if the minimum signal levels for both operating quantity and polarizing
quantity are exceeded. However, if the angle calculation is not valid, the calculated
residual power is zero. Residual power (RES_POWER) is calculated continuously and it
is available in the monitored data view. The power is given in relation to nominal power
calculated as Pn = Vn × In, where Vn and In are obtained from the entered voltage
transformer and current transformer ratios entered, and depend on the Io signal Sel and Vg
or V0 settings.
Level detector
Level detector compares the magnitudes of the measured operating quantity (residual
current IG), polarizing quantity (residual voltage VG) and calculated residual power to the
set Current pickup value (×In), Voltage pickup value (×Vn) and Power pickup value (×Pn)
respectively. When all three quantities exceed the limits, Level detector enables the Timer
module.
When calculating the setting values for Level detector, it must be considered that the
nominal values for current, voltage and power depend on whether the residual quantities
are measured from a dedicated measurement channel or calculated from phase quantities,
as defined in the Io signal Sel and Vg or V0 settings.
For residual current IG or I0, if "Measured IG" is selected, the nominal values for primary
and secondary are obtained from the current transformer ratio entered for residual current
channel Configuration/Analog inputs/Current (IG, CT). If "Calculated I0" is selected,
the nominal values for primary and secondary are obtained from the current transformer
ratio entered for phase current channels Configuration/Analog inputs/Current (3I,
CT).
For residual voltage VG or V0, if "Measured VG" is selected, the nominal values for
primary and secondary are obtained from the voltage transformer ratio entered for residual
voltage channel Configuration/Analog inputs/Voltage (VG, VT). If "Calculated V0" is
selected, the nominal values for primary and secondary are obtained from the voltage
transformer ratio entered for phase voltage channels Configuration/Analog inputs/
Voltage (3V, VT).
Section 4
Protection functions
415