• number of auto-reclosing shots
• auto-reclosing program
• auto-reclosing open times (dead time) for each shot.
10.3.2.1 Auto-reclosing operation Off and On
Operation of the automatic reclosing can be set OFF and ON by a setting parameter
and by external control. Parameter Operation = Off, or On sets the function OFF and
ON. In setting Operation=ExternalCtrl= Off and On control is made by input signal
pulses, for example, from the control system or from the binary input (and other
systems).
When the function is set On and operative (other conditions such as CB closed and CB
Ready are also fulfilled), the output SETON is activated (high) when the function is
ready to accept a reclosing start.
10.3.2.2 Start auto-reclosing and conditions for start of a reclosing cycle
The usual way to start a reclosing cycle, or sequence, is to start it at tripping by line
protection by applying a signal to the input START. Starting signals can be either,
General Trip signals or, only the conditions for Differential, Distance protection Zone
1 and Distance protection Aided trip. In some cases also Directional Earth fault
function Aided trip can be connected to start an Auto-Reclose attempt.
A number of conditions need to be fulfilled for the start to be accepted and a new auto-
reclosing cycle to be started. They are linked to dedicated inputs. The inputs are:
• CBREADY, CB ready for a reclosing cycle, for example, charged operating gear
• CBPOS to ensure that the CB was closed when the line fault occurred and start
was applied.
• No signal at input INHIBIT that is, no blocking or inhibit signal present. After the
start has been accepted, it is latched in and an internal signal Started is set. It can
be interrupted by certain events, like an Inhibit signal.
10.3.2.3 Start auto-reclosing from CB open information
If a user wants to initiate auto-reclosing from the "CB open" position instead of from
protection trip signals, the function offers such a possibility. This starting mode is
selected with the setting parameter StartByCBOpen=On. It is then necessary to block
reclosing for all manual trip operations. Typically CBAuxContType=NormClosed is
also set and a CB auxiliary contact of type NC (normally closed is connected to inputs
CBPOS and START. When the signal changes from “CB closed” to “CB open” an
auto-reclosing start pulse is generated and latched in the function, subject to the usual
checks. Then the reclosing sequence continues as usual. One needs to connect signals
from manual tripping and other functions, which shall prevent reclosing, to the input
INHIBIT.
1MRK 505 291-UEN A Section 10
Control
215
Application manual
To Next Page
Loading...
