ABB OMD800 - Description; OMD800 Switching Sequence; Line 1 Priority

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AUTOMATIC CONTROL UNIT, OMD800
AUTOMATIC CONTROL UNIT, OMD800
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3 Description
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3.1 OMD800 switching sequence
3.1.1 Line 1 priority
The switching sequence of OMD800 can be summarized in following steps:
An anomaly occurs on the Line 1
Switching delay
Generator start
Delay on transfer
If Pre-transfer signal active: Pre-trasnfer signal output on,
Pre-transfer I to II delay
Change-over switch (Switch I) to the position O
Dead band I to II delay
Change-over switch (Switch II) to the position II
If Pre-transfer signal active: Pre-transfer signal output off
And the back switching sequence can be summarized in the following steps:
The Line 1 will start the normal functioning
Back switching delay
If Pre-transfer signal active: Pre-transfer output on,
Pre-transfer II to I delay
Change-over switch (Switch II) to the position O
Dead band II to I delay
Change-over switch (Switch I) to the position I
If Pre-transfer signal active: Pre-transfer output o
Generator stop delay
Generator stop
Figure 3.1 Automatic Switching Sequences in OMD800
Ts: Switching delay, Tt: Delay on transfer, Ds: Dead band I to II, TBs: Back switching delay, DBs: Dead band II to I, Gs: Generator stop delay
Ts TBs Gs
LINE 2
LINE 1
DBs
Switch I status
Gen. START
A04155
Switch II status
Tt Ds