Ar Timing Sequence - Evolving/Permanent Fault Dual Cb; Figure 135: Dual Cb Autoreclose Sequence For A Transient Fault - GE MiCOM P40 Technical Manual

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Table of Contents

Chapter 11 - Autoreclose

Protection Trip

CB1 AR in Progress

CB2 AR in Progress

Auto -close CB1

Follower Time

Auto -close CB2

Reclaim Time

CB1 Successful close

CB2 Successful close

Following fault inception, the protection operates and issues a trip signal. At the same time an Autoreclose in

Progress signal is asserted for each CB. Shortly afterwards, CB1 will open as indicated by the CB1 Open signal and

after a short delay CB2 opens. Opening of CB2 clears the fault and the protection resets. When this happens, the

Dead Timer is started and the output remains high until the Dead Time setting expires, whereupon it resets and the

Autorecloser issues the Auto-close command to close CB1. When CB1 closes, the Follower Timer starts. When the

Follower Timer expires, the Autorecloser issues the Autoclose command to close CB2. After CB2 has closed, as the

fault has been cleared, both CBs remain closed. When the Auto-close 2 pulse is removed, the Reclaim Timer starts.

If no further fault is detected before the Reclaim Timer expires, the Autoreclose is considered to be successful and

this is indicated by the Successful Autoreclose signals.

AR TIMING SEQUENCE - EVOLVING/PERMANENT FAULT DUAL CB

The figure below shows a single-shot AR operating sequence where the fault is not cleared by the first AR cycle.

The sequence starts in a similar way to that of a transient fault, but in this case the fault is not transient (it may be

permanent, or it may evolve into a fault involving more than one phase). This case shows an evolving fault

inception occurring before the Reclaim Time has expired. When the Autorecloser recognises that the protection

has tripped, the cycle is terminated. The Autorecloser goes to Lockout, and the AR in Progress signals are reset

P446SV-TM-EN-1