Siemens siprotec 7SJ63, Инструкция по эксплуатации

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Functions
6-158
7SJ63 Manual
C53000-G1140-C120-1
tion is delayed by a fixed amount of time. For two binary inputs, the delay is about 2
seconds, and for one binary input, the delay is about 300 ms. This ensures that, for
the longest possible duration of a trip signal, a false malfunction message will not be
generated.
Monitoring with
One Binary Input NOTE: When using only one binary input (BI) for the trip circuit monitor, some mal-
functions, such as interruption of the trip circuit or loss of battery voltage, can indeed
be detected, but malfunctions with closed trip contacts cannot. Therefore, the mea-
surement must take place over a period of time that bridges the longest possible du-
ration of a closed trip contact. This is ensured by the fixed number of measurement
repetitions and the time between the condition checks.
When using only one binary input, a resistor R is inserted into the circuit on the system
side, instead of the missing second binary input. Through appropriate sizing of the re-
sistor and depending on the system relationship, a lower control voltage can often be
sufficient. The resistor R is inserted into the circuit of the 52b circuit breaker auxiliary
contact, to facilitate the detection of a malfunction when the 52a circuit breaker auxil-
iary contact open and the trip contact has dropped out (see Figure 6-66). This resistor
must be sized such that the circuit breaker trip coil is no longer energized when the
circuit breaker is open (which means 52a is open and 52b is closed). The binary input
should still be picked up when the trip contact is simultaneously opened.
This results in an upper limit for the resistance dimension, R
max
, and a lower limit R
min
,
from which the optimal value of the arithmetic mean should be selected:
In order that the minimum voltage for controlling the binary input is ensured, R
max
is
derived as:
So the circuit breaker trip coil does not remain energized in the above case, R
min
is
derived as:
If the calculation results that R
max
< R
min
, then the calculation must be repeated, with
the next lowest pickup threshold V
BI min
, and this threshold must be implemented in
the device using plug-in bridges (see Subsection 8.1.3).
For the power consumption of the resistance:
I
BI (HIGH)
Constant Current with BI on
V
BI min
Minimum Control Voltage for BI (=19 V for delivery setting for nominal voltage of 24/
48/60 V;
=88 V for delivery setting for nominal voltage of 110/125/220/250 V)
V
ST
Control Voltage for Trip Circuit
R
CBTC
DC Resistance of Circuit Breaker Trip Coil
V
CBTC (LOW)
Maximum Voltage on the Circuit Breaker Trip Coil that does not lead to Tripping
R
R
max
R
min
+
2
--------------------------------- =
R
max
V
St
V
BI min
–
I
BI (High)
---------------------------------
 
 
R
CBTC
–
=
R
min
R
CBTC
V
St
V
CBTC (LOW)
–
V
CBTC (LOW)
-------------------------------------------------
 
 
⋅
=
P
R
I
2
R
⋅
V
St
R R
CBTC
+
----------------------------
 
 
2
R
⋅
= =
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