Table 337: 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".
The
Characteristic angle setting is used in the "Phase angle" mode to adjust the
operation according to the method of neutral point earthing so that in an isolated
network the
Characteristic angle (φ
RCA
) = -90° and in a compensated network φ
RCA
= 0°. In addition, the characteristic angle can be changed via the control signal
RCA_CTL. RCA_CTL affects the
Characteristic angle setting.
The
Correction angle setting can be used to improve selectivity due the inaccuracies
in the measurement transformers. The setting decreases the operation sector. The
correction can only be used with the "IoCos" or "IoSin" modes.
1MRS758755 C
Protection functions
REC615 & RER615
Technical Manual
297
