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.
Table 318: 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.
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".
Section 4 1MRS758755 A
Protection functions
282 REC615 and RER615
Technical Manual
To Next Page
Loading...
