Woodward LS-5 v2 Series - Function

A problem occurs, if breaker feedbacks are wired wrongly to the device. This would lead
to a dead busbar closure onto a live load busbar and can cause damage. In the
mentioned example above this would mean that the CBB is closed without
synchronization onto a live load busbar. Because of the inverted breaker feedback
connections the LS-5x2 automatically reacts more secure to a broken wire feedback. More
critical is a wrong connection or the fact that a power source feeds the load busbar
unintentionally.
The following proposal can prevent this circumstance.
6.6.2 Function
Equip the CBA/CBB constellation with a simple voltage relay. This relay signals the LS-5x2
whether the load busbar is dead or not. This information is taken into account by the LS-5
to act properly.
CBA
LS-5x2
System A System B
CBB
Load
System A
Feedback CBA is open (DI8)
Feedback CBB is open (DI5)
System B
Open CBA
Close CBA
Open CBB
Close CBB
Load busbar is dead (DI2)
Voltage
relay
Fig. 160: Example: The voltage relay informs by DI 2 about the load busbar condition.
In this proposal the discrete input 2 is used for the load busbar signal.
293LS-5 v2 Series37650
6 Application
6.6 Breaker Feedback Security Procedure
Released