14.2.3.5 Delta V and delta I
Set the operation mode selector OpDVDI to Enabled if the delta function shall be in
operation.
The setting of DVPU should be set high (approximately 60% of VBase) and the current
threshold DIPU low (approximately 10% of IBase) to avoid unwanted operation due to
normal switching conditions in the network. The delta current and delta voltage function
shall always be used together with either the negative or zero sequence algorithm. If
VSet
prim
is the primary voltage for operation of dU/dt and ISet
prim
the primary current for
operation of dI/dt, the setting of DVPU and DIPU will be given according to equation
531
and equation 532.
EQUATION1765-ANSI V2 EN (Equation 531)
ANSIEQUATION2385 V2 EN (Equation 532)
The voltage thresholds VPPU is used to identify low voltage condition in the system. Set
VPPU below the minimum operating voltage that might occur during emergency
conditions. A setting of approximately 70% of VBase is recommended.
The current threshold 50P shall be set lower than the IMinOp for the distance protection
function. A 5...10% lower value is recommended.
14.2.3.6 Dead line detection
The condition for operation of the dead line detection is set by the parameters IDLDPU for
the current threshold and UDLD< for the voltage threshold.
Set the IDLDPU with a sufficient margin below the minimum expected load current. A
safety margin of at least 15-20% is recommended. The operate value must however
exceed the maximum charging current of an overhead line, when only one phase is
disconnected (mutual coupling to the other phases).
Set the VDLDPU with a sufficient margin below the minimum expected operating
voltage. A safety margin of at least 15% is recommended.
14.3 Fuse failure supervision VDSPVC (60)
Section 14 1MRK 506 369-UUS -
Secondary system supervision
628 Line distance protection REL670 2.2 ANSI
Application manual
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