[anschlussbsp-ext-schutzger-fehlerab-pause-wlk-310702, 1, en_GB]
Figure 2-12
Connection example with external protection device for fault detection dependent dead time
— dead time control by pickup signals of the protection device; AR control mode = with
PICKUP
2 Protection Relays with 2 Automatic Reclosure Circuits
If redundant protection is provided for a line and each protection operates with its own automatic reclosure
function, a certain signal exchange between the two combinations is necessary. The connection example in
Figure 2-13 shows the necessary cross-connections.
If the auxiliary contacts of the circuit breaker are connected to the correct phases, a 3-pole coupling by the
7VK61 is ensured when more than one CB pole is tripped. This requires the activation of the forced 3-pole trip
(see Section 2.2.2 Setting Notes at margin heading “Forced 3-pole trip”). An external automatic 3-pole
coupling is therefore unnecessary if the above conditions are met. This prevents 2-pole tripping under all
circumstances.
For the connection according to Figure 2-13 it must be considered that the cross connections to the second
protection must be interrupted during the check of one of the two protection systems with protection moni-
toring equipment. This is done, for example, by means of a test switch installed in between.
Alternatively, the variant with a minimum cross connection according to Figure 2-14 can be applied. In this
case, the following information should be considered:
•
The switching state of the circuit breaker must be connected in a phase-selective way via the auxiliary
contacts to the corresponding binary inputs of both protection systems in case of a 1-pole reclosure. If
only 3- pole tripping is possible, the 3-pole status is sufficient.
•
In order to prevent that a very quick response (1-pole) of a protection leads to an undesired 3-pole
coupling of a second protection, a “software filter time” for the binary inputs of the auxiliary contacts is to
be set (refer to Figure 2-15).
Functions
2.2 Automatic reclosure function (optional)
SIPROTEC 4, 7VK61, Manual 55
C53000-G1176-C159-5, Edition 05.2018
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