Tasks Of The Automatic Transfer Switch; Operation Of The Automatic Transfer Switch - Viessmann Vitocharge VX3 Backup-Box 3PH A Installationsanleitung

2.1.6 Tasks of the Automatic Transfer Switch

 Disconnection of connection X2 (backup consumers) at all poles from the supply grid in the event of mains failure/mains
malfunction.
• Connection of the neutral conductor of the power storage system or of the connection X2 - „backup consumers" with the
protective earth connection to establish the protective measure „Automatic disconnection of the power supply in the TN
system". according to DIN VDE 0100-410
 Reconnection on mains return/network malfunction clearance
The total load of the load circuits at the connection X2 – „backup consumers" in backup operation should not be higher than the
maximum power that the used power storage system Vitocharge VX3, Type 6.0A/8.0A can provide when the power is drawn from
the integrated storage.

2.1.7 Operation of the Automatic Transfer Switch

The Automatic Transfer Switch communicates with regard to the grid switching by means of digital in- and outputs with the power
storage system.
The all-pole disconnection of the supply grid from the backup power consumers and the simultaneous switchover from grid to backup
power operation is carried out automatically for at least one phase by the operation management of the power storage system.
The power storage system detects the power failure and automatically activates the island grid operation after a few seconds.
 During mains parallel operation, the mains contactor K1 and earthing contactor K2 are activated and connect the power storage
system and the connection "backup-consumers" to the grid.
 In the event of a grid failure, the mains contactor K1 and the earthing contactor K2 drop off automatically or are controlled via X4
by the power storage system to disconnect. By evaluating an NC auxiliary contact of K1 and K2 at the digital input of the power
storage system, the system receives the information about the state of change of K1 and K2.
 The mains contactor K1 disconnects the grid at all poles by means of its now open NO contacts (make contact). In addition, the
neutral conductor of the island network is earthed immediately after the grid disconnection by means of the now closed NC
contacts (break contacts) of K2.
 Before the transition to island grid operation, the digital output in the power storage system, which is designed as a normally
closed contact, is activated in order to to prevent the mains contactor K1 and the earthing contactor K2 from being immediately
re-energised when the mains supply returns.
 The power storage system then establishes the island grid and remains in island grid operation until the grid supply returns. The
consumers connected to the "backup-consumers" connection are supplied with backup power during this time.
 The power storage system detects the return of the grid supply by means of an appropriate information provided by the energy
meter E3100CB. The island grid operation is then terminated and then the mains contactor K1 is activated again by deactivating
the digital output. From this moment on, the consumers and if necessary producers connected to the connection "backup-
consumers" are re-connected to the grid.
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