System-disconnection relay EU400 NA-protection
29
Subject to technical changes
12.8 Switching conditions
After switching-on the auxiliary voltage the relays only switch-on when the switch-back limit (switching
conditions / limit ± hysteresis) of all alarms have been reached.
With the parameter
UFon
, the behaviour of the switching conditions after a off-limit violation can be
determined:
UFon
→
on
the switch-back limits of the alarms undervoltage, underfrequency and overfrequency
must be fulfilled for switch-on
UFon
→
oFF
only the switch-back limit of triggered alarm must be fulfilled for switch-on
12.9 Disengaging ratio
The disengaging ratio is the ratio between the disengaging value and the start value. The start value is the
value at which the limit is recognized and the on-delay time
8
dAL
starts. The disengaging value is the value
at which
8
dAL
stops running if it reached before
8
dAL
expires.
Activate the
ruEF
function for simple measurement of the disengaging ratio.
Function while
ruEF
is active:
When limit value is reached (=
8
dAL
starts)
→
relay OFF.
When the disengaging value is reached (=
8
dAL
cancelled)
→
relays ON.
Disengaging ratios can only be checked for U>>, U>, U<, U<< (not for f, zero voltage and 10min average
value). For testing e.g. U >>, U> must be switched "off."
8
ruEF
can be selected under the menu item
8
rEL
→
8
doFA
. The "time" LED flashes when
8
ruEF
is active.
To switch off the function select
rEL
→
doFA
→
All
and confirm with “set”. The delay-off time
doF
for all
alarms can be set here to the values required by the system operator. The function switches off automatically
after 600 s.
12.10
Monitoring of zero voltage
The zero voltage U
0
(ANSI 59v0) is the modulus of the zero-component system,
𝑈
0
= |𝑈
0
|
. The zero-
component system is an operand from the phase-to-neutral voltages (
𝑈
𝐿1
, 𝑈
𝐿2
, 𝑈
𝐿3
) and the phase angels
(
𝜑
𝐿12
, 𝜑
𝐿23
, 𝜑
𝐿31
) and is defined by the following equation:
𝑈
0
=
1
3
∗ (𝑈
𝐿1
+ 𝑈
𝐿2
+ 𝑈
𝐿3
)
.
Activate the
U-0
function for simple measurement of the zero voltage. All other parameters such as limit
value, hysteresis and delay times can be set under this menu item.
Function while
U-0
is active:
When limit value is reached (=
8
dAL
starts)
→
relay OFF. This state is indicated by flashing-on the LED
and switching-on of the digital outputs Q1 and Q2, respectively.
When the fallback value is reached (=
8
doF
starts)
→
relay ON. LED/ digital outputs Q1+Q2 off.
