Siemens SIPROTEC 4 7SJ61 Manual page 65

In order to represent the characteristic graphically, the user should click on "characteristic". The previously
entered characteristic will appear as shown in
The characteristic curve shown in the graph can be modified later on. Placing the mouse cursor over a point
on the characteristic, the cursor changes to the shape of a hand. Press and hold the left mouse button and
drag the data item to the desired position. Releasing the mouse button will automatically update the value in
the value table.
The respective upper limits of the ranges of value are indicated by dotted lines in the right-hand and upper
area of the system of coordinates. If the position of a data point lies outside these limits, the associated value
is set to infinity.
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Figure 2-16
Inrush Restraint
When applying the protection device to transformers where high inrush currents are to be expected, the
7SJ61 can make use of an inrush restraint function for the overcurrent elements 50-1, 51, 50N-1 and 51N.
Inrush restraint is only effective and accessible if address 122 InrushRestraint was set to Enabled. If this
function is not required, then Disabled is set. In address 2201 INRUSH REST., the function is switched ON
or OFF jointly for the overcurrent elements 50-1 PICKUP,51 PICKUP, 50N-1 PICKUP and 51N PICKUP
The inrush restraint is based on the evaluation of the 2nd harmonic present in the inrush current. Upon
delivery from the factory, a ratio Ι
be changed. The setting value is identical for all phases and ground. However, the component required for
restraint may be adjusted to system conditions in address 2202 2nd HARMONIC. To provide more restraint in
exceptional cases, where energizing conditions are particularly unfavorable, a smaller value can be set in the
aforementioned address, e.g. 12 %. Irrespective of parameter 2202 2nd HARMONIC, rush blocking will only
occur if the absolute value of the 2nd harmonic is at least 0.125 * INom,sec.
The effective duration of the cross-blocking 2203 CROSS BLK TIMER can be set to a value between 0 s
(harmonic restraint active for each phase individually) and a maximum of 180 s (harmonic restraint of a phase
blocks also the other phases for the specified duration).
If the current exceeds the value set in address 2205 I Max, no further restraint will take place for the 2nd
harmonic.
Manual Close Mode (phases ground)
When a circuit breaker is closed onto a faulted line, a high-speed trip by the circuit breaker is usually desired.
For overcurrent or high-set element the delay may be bypassed via a Manual Close pulse, thus resulting in
instantaneous tripping. The internal "Manual close" signal is built from the binary input signal >Manual Close
(no. 356 ). The internal "Manual close" signal remains active as long as the binary input signal >Manual Close is
active, but at least for 300 ms (see the following logic diagram). To enable the device to react properly on
occurrence of a fault in the phase element, address 1213 MANUAL CLOSE has to be set accordingly. Corre-
spondingly, address 1313 MANUAL CLOSE is considered for the ground path address. Thus, the user deter-
SIPROTEC 4, 7SJ61, Manual
C53000-G1140-C210-6, Edition 05.2016
Entry and visualization of a user-defined tripping characteristic in DIGSI — example
/Ι of 15 % is set. Under normal circumstances, this setting will not need to
2f f
2.2 Overcurrent Protection 50, 51, 50N, 51N
Figure 2-16.
Functions
65