redundancy PM861A 3BSE018157R1

redundancy PM861A 3BSE018157R1

redundancy PM861A 3BSE018157R1

In many cases there is a requirement that a Lock-out is generated when the autoreclosing attempt fails. This is done with logic connected to the in- and outputs of the Autoreclose function and connected to Binary IO as required. Many alternative ways of performing the logic exist depending on whether manual closing is interlocked in the IED, whether an external physical Lock-out relay exists and whether the reset is hardwired, or carried out by means of communication. There are also different alternatives regarding what shall generate Lock-out.

Examples of questions are:

• Shall back-up time delayed trip give Lock-out (normally yes)

• Shall Lock-out be generated when closing onto a fault (mostly)

• Shall Lock-out be generated when the Autorecloser was OFF at the fault or for example, in Single phase AR mode and the fault was multi-phase (normally not as no closing attempt has been given)

• Shall Lock-out be generated if the Breaker did not have sufficient operating power for an auto-reclosing sequence (normally not as no closing attempt has been given) In figures 319 and 320 the logic shows how a closing Lock-out logic can be designed with the Lock-out relay as an external relay alternatively with the Lock-out created internally with the manual closing going through the Synchro-check function. An example of Lock-out logic.