current Io: Configuration> Analog inputs> Current (Io,CT): 100 A : 1 A. The Residual
voltage Uo: Configuration> Analog inputs> Voltage (Uo,VT): 11.547 kV : 100 V. The
Start value
of 1.0 × In corresponds to 1.0 * 100 A = 100 A in the primary. The
Voltage
start value
of 1.0 × Un corresponds to 1.0 * 11.547 kV = 11.547 kV in the primary.
Example 2: Both Io and Uo are calculated from the phase quantities. Phase CT-
ratio is 100 : 1 A and phase VT-ratio is 20/sqrt(3) kV : 100/sqrt(3) V. In this case,
"Calculated Io" and "Calculated Uo" are selected. The nominal values for residual
current and residual voltage are obtained from CT and VT ratios entered in Residual
current Io: Configuration> Analog inputs> Current (3I,CT): 100 A : 1 A. The residual
voltage Uo: Configuration> Analog inputs> Voltage (3U,VT): 20.000 kV : 100 V. The
Start value
of 1.0 × In corresponds to 1.0 * 100 A = 100 A in the primary. The
Voltage
start value
of 1.0 × Un corresponds to 1.0 * 20.000 kV = 20.000 kV in the primary.
If "Calculated Uo" is selected, the residual voltage nominal value is always
phase-to-phase voltage. Thus, the valid maximum setting for residual
Voltage start value is 0.577 x Un. The calculated Uo requires that all the
three phase-to-earth voltages are connected to the protection relay. Uo
cannot be calculated from the phase-to-phase voltages.
If the
Enable voltage limit
setting is set to "True", the magnitude of the
polarizing quantity is checked even if the
Directional mode
was set to
"Non-directional" or
Allow Non Dir
to "True". The protection relay does
not accept the
Start value
or
Start value Mult
setting if the product of
these settings exceeds the
Start value
setting range.
Typically, the ENA_MULT input is connected to the inrush detection function
INRHPAR. In case of inrush, INRPHAR activates the ENA_MULT input, which multiplies
Start value
by the
Start value Mult
setting.
Directional calculation
The directional calculation module monitors the angle between the polarizing
quantity and operating quantity. Depending on the
Pol quantity
setting, the
polarizing quantity can be the residual voltage (measured or calculated) or the
negative sequence voltage. When the angle is in the operation sector, the module
sends the enabling signal to the timer module.
The minimum signal level which allows the directional operation can be set with the
Min operate current
and
Min operate voltage
settings.
If
Pol quantity
is set to "Zero. seq. volt", the residual current and residual voltage are
used for directional calculation.
If
Pol quantity
is set to "Neg. seq. volt", the negative sequence current and negative
sequence voltage are used for directional calculation.
In the phasor diagrams representing the operation of (F)DEFxPDEF, the polarity of
the polarizing quantity (Uo or U2) is reversed, that is, the polarizing quantity in the
phasor diagrams is either -Uo or -U2. Reversing is done by switching the polarity
of the residual current measuring channel. Similarly the polarity of the calculated Io
and I
2
is also switched.
For defining the operation sector, there are five modes available through the
Operation mode
setting.
Protection functions
1MRS758755 C
296 REC615 & RER615
Technical Manual
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