TB XRI1-IE 11.01 E
17
6
Operations and settings
6.1
Setting procedure
After push button <SELECT/RESET> has been pressed,
always the next measuring value is indicated. Firstly
the operating measuring values are indicated and then
the setting parameters. By pressing the <ENTER> push
button the setting values can directly be called up and
changed.
6.1.1
Pickup current for phase
overcurrent element (I>)
The setting value for this parameter that appears on the
display is related to the nominal current (I
N
) of the re-
lay. This means: pickup current (Is) = displayed value x
nominal current (I
N
) e.g. displayed value = 1.25 then,
Is = 1.25 x IN.
6.1.2
Time current characteristics for
phase overcurrent element
(CHAR I>)
By setting this parameter, one of the following 4 mes-
sages appears on the display:
DEFT -
Definite Time
NINV -
Normal Inverse (type A)
VINV -
Very Inverse (type B)
EINV -
Extremely Inverse (type C)
Anyone of these four characteristics can be chosen by
using <+> <-> push buttons, and can be stored by us-
ing <ENTER> push button.
6.1.3
Trip delay or time multiplier for
phase overcurrent element (t
I>
)
Usually, after the characteristic is changed, the time
delay or the time multiplier should be changed accord-
ingly. In order to avoid an unsuitable arrangement of
relay modes due to carelessness of the operator, the
following precautions are taken:
After the characteristic setting, the setting process turns
to the time delay setting automatically. The LED tI> is
going to flash yellow to remind the operator to change
the time delay setting accordingly. After pressing the
<SELECT> push button, the present time delay setting
value is shown on the display. The new setting value
can then be changed by using <+> <-> push buttons.
If, through a new setting, another relay characteristic
other than the old one has been chosen (e.g. from
DEFT to NINV), but the time delay setting has not been
changed despite the warning from the flashing LED,
the relay will be set to the most sensitive time setting
value of the selected characteristics after five minutes
warning of flashing LED tI>. The most sensitive time set-
ting value means the fastest tripping for the selected re-
lay characteristic. When the time delay or the time
multiplier is set out of range (Text "EXIT" appears on the
display), the low set element of the overcurrent relay is
blocked. The "WARN"-relay will not be blocked.
6.1.4
Reset setting for inverse time
tripping characteristics in the phase
current path
To ensure tripping, even with recurring fault pulses
shorter than the set trip delay, the reset mode for in-
verse time tripping characteristics can be switched
over. If the adjustment tRST is set at 60s, the tripping
time is only reset after 60s faultless condition. This
function is not available if tRST is set to 0. With fault
current cease the trip delay is reset immediately and
started again at recurring fault current.
6.1.5
Current setting for high set element
(I>>)
The current setting value of this parameter appearing
on the display is related to the nominal current of the
relay.
This means: I>> = displayed value x I
N
.
When the current setting for high set element is set out
of range (on display appears "EXIT"), the high set ele-
ment of the overcurrent relay is blocked.
The high set element can be blocked via terminals
C1/C1L or C1/C1H if the corresponding blocking
parameter is set to bloc (refer to chapter 6.1.20).
