Application Guide - NP900 Series
413 (504
)
A996A
Figure 3.6.4.9-196 Autoreclosing with distributed generation in the line.
For this operation there needs to be communication link in between of the substation
master relay and 20 kV collector station incomer follower relay. When autoreclosing is
initiated the collector station breaker is opened until the autoreclosing cycle is completed.
If the autoreclosing is not successful from the 20 kV substation towards the collector
station there is no point to allow the closing of the collector station breaker either. In case
the autoreclosing cycle is successful after reclaim time the close permission for the
collector station can be given and the breaker should be closed with synchroswitch
function.
After the collector station is disconnected the basic principles of autoreclosing can be
applied for the overhead line as described previously. This same principle should apply for
any ring or meshed network where in the same line power can be fed from more than one
direction. For typical consumer radial network this problem does not exist.
3.6.4.10
A
RCING TIME AND
D
ISCRIMINATION TIME
After the Dead time has elapsed and the breaker is closed by autorecloser, behavior of
the autorecloser can be set in various ways. Generally after breaker is closed Reclaim
time starts running and if during this Reclaim time new reclosing request occurs
Autorecloser shall continue to next state whether it would be next shot or in case all shots
have been used to Final Trip.
The entering to next state can be controlled by Arcing time and Discrimination time
settings. These settings are either or type which means that if Arcing time is selected
Discrimination time cannot be selected for same request and same shot simultaneously.
