SYN5202a-Z,V221 3BHB006715R0221 Synchronizing devices and systems

From a synchronizing device, it is expected to close the power circuit breaker at the correct time but also that, if
required, paralleling can take place whenever permissible. Although the series connection of the output contacts of two
independently-functioning channels (dual-channel system), which is usual in synchronizing systems, greatly increases
security against incorrect paralleling, it necessarily leads to a reduction in availability

Single or dual-channel?
Not every synchronizing system needs to be structured according to the above pattern. The SYNCHROTACT® 5
single-channel synchronizing devices offer a high degree of security and are often used in practice. However, security
can be significantly increased by means of dual-channel systems. It is unlikely that the two channels – of which the
hardware and software are structured differently – will have the same malfunction simultaneously. The extra cost of a
dual channel system can prove beneficial compared to the damage arising from incorrect paralleling.
Second, redundant synchronizing system?
Often, two redundant synchronizing systems are installed in a single plant so that, in the event of one system failing,
the other can be used, thereby increasing availability. The second system is often designed for manual synchronizing
with or without synchrocheck.
In addition, with SYNCHROTACT® 5, ABB offers two automatic dual-channel systems in a single casing, thus avoiding
manual synchronizing.
Advantages of such a solution:
– No engineering and wiring costs for the second system
– Further increased security since all four output contacts are normally operated in series
– No problems with synchronizing where the manual synchronizing system is seldom used.