Table of Contents
Advertisement
If you want the voltage at the remote line end to be decisive for overvoltage detection,
you use the compounding feature. To do so, you must have set during the configura-
tion of the protective functions (Section 2.1.1.2) address 137 U/O VOLTAGE to
Enabl. w. comp. (enabled with compounding).
In addition, the compounding feature needs the line data, which have been set in the
General Protection Data (Power System Data 2) (Section 2.1.4.1):
Address 1111 x', address 1112 c' and address 1113 Line Length, as well as
address 1105 Line Angle. These data are vital for a correct compounding calcula-
tion. If the values provided here do not correspond to real conditions, the compound-
ing may calculate a too high voltage at the remote end, which will cause immediate
pickup as soon as the measured values are applied. In such a case, the pickup state
can only be reset by switching off the measuring voltage.
Compounding can be switched ON or OFF separately for each of the U1 stages: for the
U1> stage at address 3736 U1> Compound and for the U1>> stage at address 3737
U1>> Compound.
The dropout to pickup ratio (address 3739 U1>(>) RESET) is set as high as possible
with regard to the detection of even small steady-state overvoltages. This parameter
can only be altered in DIGSI at Display Additional Settings.
Overvoltage nega-
The negative sequence voltage stages detect asymmetrical voltages. If such voltages
should cause tripping, set address 3741 U2>(>) to ON. If you want only an alarm to
tive sequence
be generated, set address 3741 U2>(>) to Alarm Only. If you want only one stage
system U
2
to generate a trip command, choose the setting U>Alarm U>>Trip. With this setting
a trip command is output by the 2nd stage only. If negative sequence voltage protec-
tion is not required, set this parameter to OFF.
This protective function also has two stages, one being U2> (address 3742) with a
greater time delay T U2> (address 3743) for steady-state asymmetrical voltages and
the other being U2>> (address 3744) with a short delay time T U2>> (address 3745)
for high asymmetrical voltages.
Note that the negative sequence system is established according to its defining equa-
tion U
phases this is equivalent to the phase–to–earth voltage value.
The dropout to pickup ratio U2>(>) RESET can be set in address 3749. This param-
eter can only be altered in DIGSI at Display Additional Settings.
The zero sequence voltage stages can be switched ON or OFF in address 3721
Overvoltage zero
3U0>(>) (or Ux). They can also be set to Alarm Only, i.e. these stages operate
sequence system
and send alarms but do not generate any trip commands. If you want a trip command
of the 2nd stage to be created anyway, the setting must be U>Alarm U>>Trip. This
protection function can be used for any other single-phase voltage which is connected
to the fourth voltage measurement input U
margin heading „Voltage Transformer Connection".
This protective function also has two stages. The settings of the voltage threshold and
the timer values depend on the type of application. Here no general guidelines can be
established. The stage 3U0> (address 3722) is usually set with a high sensitivity and
a longer delay time T 3U0> (address 3723). The 3U0>> stage (address 3724) and
its delay time T 3U0>> (address 3725) allow you to implement a second stage with
less sensitivity and a shorter delay time.
Similar considerations apply if this voltage stage is used for a different voltage at the
measuring input U
7SD610 Manual
C53000-G1176-C145-4
2.11 Undervoltage and Overvoltage Protection (optional)
1
2
=
/
·|U
+ a
·U
+ a·U
2
3
L1
L2
.
4
|. For symmetrical voltages and two swapped
L3
. Also refer to Section 2.1.2.1 and see
4
163
Advertisement
Table of Contents
