Dead Line Detection - ABB RELION RET670 Applications Manual

Section 14
Secondary system supervision
14.2.3.5
14.2.3.6
672
3 0 I
3 0 I PU 100
= ×
IBase
EQUATION2293-ANSI V2 EN-US
where:
3I0PU
is the maximal zero sequence current during normal operating conditions, plus a margin of
10...20%
IBase is the base current for the function according to the setting
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 is the primary voltage for operation of dU/dt and ISet
prim
primary current for operation of dI/dt, the setting of DVPU and DIPU will be given
according to equation 501
VSet
prim
DVPU
= ⋅100
VBase
EQUATION1765-ANSI V2 EN-US
ISet
prim
DIPU
= ⋅100
IBase
ANSIEQUATION2385 V2 EN-US
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.

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.
and equation 502.
1MRK 504 163-UUS A
(Equation 500)
GlobalBaseSel
GUID-02336F26-98C0-419D-8759-45F5F12580DE v7
prim
(Equation 501)
(Equation 502)
Transformer protection RET670 2.2 ANSI
Application manual
the
M13683-78 v4