ABB RELION 670 Series Applications Manual page 310

Section 7
Impedance protection
TimerModeZx =
Enable Ph-Ph,
Ph-E
BLOCK
VTSZ
BLKZx
BLKTRZx
IEC12000139 V3 EN-US
Figure 174: Logic for linking of timers
CVTtype
If possible, the type of capacitive voltage transformer (CVT) used for measurement should be
identified. The alternatives are strongly related to the type of ferro-resonance suppression
circuit included in the CVT. There are two main choices:
Passive type
Any
None
(Magnetic)
INReleasePE
This setting opens an opportunity to enable phase-to-earth measurement for phase-to-phase-
earth faults. It determines the level of residual current (3I0) above which phase-to-earth
measurement is activated (and phase-to-phase measurement is blocked). The relations are
defined with the equation.
304
PPZx AND
PEZx AND
OR
ZoneLinkStart
STPHS Phase Selection
1st starting zone
LNKZ1
LNKZ2
LNKZRV
LNKZ3 OR
LNKZ4
LNKZ5
For CVTs that use a nonlinear component, like a saturable inductor, to limit overvoltages
(caused by ferro-resonance). This component is practically idle during normal load and fault
conditions, hence the name "passive." CVTs that have a high resistive burden to mitigate
ferro-resonance also fall into this category.
This option is primarily related to the so-called active type CVT, which uses a set of reactive
components to form a filter circuit that essentially attenuates frequencies other than the
nominal to restrain the ferro-resonance. The name "active" refers to this circuit always being
involved during transient conditions, regardless of the voltage level. This option should also
be used for the types that do not fall under the other two categories, for example, CVTs with
power electronic damping devices, or if the type cannot be identified at all.
This option should be selected if the voltage transformer is fully magnetic.
tPPZx
OR AND
AND
t
tPEZx
OR
AND
t
AND
TimerLinksZx
OR
LoopLink (tPP-tPE)
LoopLink & ZoneLink
OR
No Links
FALSE (0)
TimerLinksZx =
LoopLink & ZoneLink
1MRK 504 152-UEN B
TZx
OR
LNKZx
AND
IEC12000139-3-en.vsdx
Application manual