ABB RELION REX640 - Page 455

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 in the Protection relay's
physical connections section). 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 530: 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 neg-
ative. 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.
The network rotating direction is set in the protection relay using the
parameter in the HMI menu: Configuration> System> Phase rotation.
The default parameter value is "ABC".
If the Enable voltage limit setting is set to "True", the magnitude of
the polarizing quantity is checked even if Directional mode is set to "Non-
directional" or Allow Non Dir to "True".
1MRS759142 F Protection functions
REX640
Technical Manual
455