11.3.6.6 Reclosing checks and the reset timerWhen dead time has elapsed during the auto-reclosing procedure certain conditions mustbe fulfilled before the CB closing command is issued. To achieve this, signals areexchanged between program modules to check that these conditions are met. In three-phase reclosing a synchronizing and/or energizing check can be used. It is possible to use asynchronism check function in the same physical device or an external one. The releasesignal is configured by connecting to the auto-reclosing function input SYNC. If reclosingwithout checking is preferred the SYNC input can be set to TRUE (set high). Atconfirmation from the synchronism check, or if the reclosing is of single-phase, the signalpasses on.By choosing CBReadyType = CO (CB ready for a Close-Open sequence) the readiness ofthe circuit breaker is also checked before issuing the CB closing command. If the CB hasa readiness contact of type CBReadyType = OCO (CB ready for an Open-Close-Opensequence) this condition may not be complied with after the tripping and at the moment ofreclosure. The Open-Close-Open condition was however checked at the start of thereclosing cycle and it is then likely that the CB is prepared for a Close-Open sequence.The synchronism check or energizing check must be fulfilled within a set time interval,tSync. If it is not, or if other conditions are not met, the reclosing is interrupted andblocked.The reset timer defines a time from the issue of the reclosing command, after which thereclosing sequence resets. Should a new trip occur during this time, it is treated as acontinuation of the first fault. The reset timer is started when the CB closing command isgiven.A number of outputs for Autoreclosing state control keeps track of the actual state in thereclosing sequence.1MRK 506 335-UUS A Section 11Control383Technical manual
