P44x/EN AP/Hb
MiCOM P40 Agile P442, P444
(AP) 5-
Figure 111: Autoreclose timing diagram
Should autoreclosure not be required, the function may be Disabled in the relay
Configuration menu. Disabling the autorecloser does not prevent the use of the internal
check synchronism element to supervise manual circuit breaker closing.
An autoreclose cycle is internally initiated by operation of a protective element (could be
started by an internal trip or external trip), provided the circuit breaker is closed at the instant
of protection operation. The appropriate dead time-delay for the shot is started (Dead Time
1, 2, 3 or 4; noting that separate dead times are provided for the first high speed shot of
single pole (1P), and three pole (3P), reclosure). At the end of the dead time, a CB close
pulse command of ‘Close Pulse Time’ duration (see section 5.1: ‘CB Control” menu) is
given, provided system conditions are suitable.
The reclaim time (Reclaim Time) starts with the CB Close pulse. If the circuit breaker has
not been retripped, the autoreclose logic is reset at the end of the reclaim time. The
autorecloser is ready again to start a new cycle again from the first shot a new cycle again
(for future faults). If the protection retrips during the reclaim time, the relay either advances to
the next shot in the programmed autoreclose cycle, or, if all programmed reclose attempts
have been made, goes to lockout.
The following timing diagram illustrates the P44x autoreclose cycle (1P / 3P trip) in normal
condition:
Figure 112: Autoreclose cycle – general description
The conditions to be met for closing are that the system voltages satisfy the internal check
synchronism criteria (see Check synchronisation section), and that the circuit breaker closing
spring, or other energy source, is fully charged. The following diagram illustrates a second
trip command before the end of reclaim time:
Figure 113: Successive autoreclose cycles
To Next Page
Loading...
Need help?
General
