Table 344: Momentary operating direction
Fault direction
The value for DIRECTION
Angle between the polarizing and operating
quantity is not in any of the defined sectors.
0 = unknown
Angle between the polarizing and operating
quantity is in the forward sector.
1= forward
Angle between the polarizing and operating
quantity is in the reverse sector.
2 = backward
Angle between the polarizing and operating
quantity is in both the forward and the re-
verse sectors, that is, the sectors are overlap-
ping.
3 = both
If the
Allow Non Dir setting is "False", the directional operation (forward, reverse)
is not allowed when the measured polarizing or operating quantities are invalid,
that is, their magnitude is below the set minimum values. The minimum values
can be defined with the settings
Min operate current and Min operate voltage.
In case of low magnitudes, the
FAULT_DIR
and
DIRECTION
outputs are set to
0 = unknown, except when the
Allow non dir setting is "True". In that case, the
function is allowed to operate in the directional mode as non-directional, since the
directional information is invalid.
Iosin(φ) and Iocos(φ) criteria
A more modern approach to directional protection is the active or reactive current
measurement. The operating characteristic of the directional operation depends
on the earthing principle of the network. The Iosin(φ) characteristics is used in an
isolated network, measuring the reactive component of the fault current caused
by the earth capacitance. The Iocos(φ) characteristics is used in a compensated
network, measuring the active component of the fault current.
The operation criteria Iosin(φ) and Iocos(φ) are selected with the
Operation mode
setting using the values "IoSin" or "IoCos" respectively.
The angle correction setting can be used to improve selectivity. The setting
decreases the operation sector. The correction can only be used with the Iosin(φ) or
Iocos(φ) criterion. The
RCA_CTL
input is used to change the Io characteristic:
Table 345: Relay characteristic angle control in the IoSin and IoCos operation
criteria
Operation mode:
RCA_CTL
= "False"
RCA_CTL
= "True"
IoSin
Actual operation criterion: Io-
sin(φ)
Actual operation criterion: Io-
cos(φ)
IoCos
Actual operation criterion: Io-
cos(φ)
Actual operation criterion: Io-
sin(φ)
When the Iosin(φ) or Iocos(φ) criterion is used, the component indicates a forward-
or reverse-type fault through the
FAULT_DIR
and
DIRECTION
outputs, in which 1
equals a forward fault and 2 equals a reverse fault. Directional operation is not
allowed (the
Allow non dir setting is "False") when the measured polarizing or
operating quantities are not valid, that is, when their magnitude is below the set
minimum values. The minimum values can be defined with the
Min operate current
Protection functions
1MRS758755 C
310
REC615 & RER615
Technical Manual
