ABB Relion 611 Series, Technical Manual

Page: 181 / 536

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 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 (see the connection diagram in the application
manual). 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.
Table 179: Operation modes
Operation mode Description
Phase angle The operating sectors for forward and reverse are
defined with the settings Min forward angle, Max
forward angle, Min reverse angle and Max reverse
angle.
IoSin The operating sectors are defined as "forward"
when |Io| x sin (ANGLE) has a positive value and
"reverse" when the value is negative. ANGLE is
the angle difference between -Uo and Io.
IoCos As "IoSin" mode. Only cosine is used for
calculating the operation current.
Phase angle 80 The sector maximum values are frozen to 80
degrees respectively. Only
Min forward angle and
Min reverse angle are settable.
Phase angle 88 The sector maximum values are frozen to 88
degrees. Otherwise as "Phase angle 80" mode.
Polarizing quantity selection "Neg. seq. volt." is available only in the
"Phase angle" operation mode.
The directional operation can be selected with the Directional mode setting. The
alternatives are "Non-directional", "Forward" and "Reverse" operation. The operation
criterion is selected with the
Operation mode setting. By setting Allow Non Dir to
"True", non-directional operation is allowed when the directional information is
invalid, that is, when the magnitude of the polarizing quantity is less than the value of
the
Min operate voltage setting.
Typically, the network rotating direction is counter-clockwise and defined as "ABC".
If the network rotating direction is reversed, meaning clockwise, that is, "ACB", the
equation for calculating the negative sequence voltage component need to be changed.
The network rotating direction is defined with a system parameter
Phase rotation . The
calculation of the component is affected but the angle difference calculation remains
the same. When the residual voltage is used as the polarizing method, the network
rotating direction change has no effect on the direction calculation.
1MRS757454 D
Section 4
Protection functions
611 series 175
Technical Manual