ABB Relion REQ650, Руководство по применению

Страница: 231 / 340

PREP3P
Prepare three-phase trip is usually connected to the trip block to force a coming trip to
be a three-phase one. If the function cannot make a single- or two-phase reclosing, the
tripping should be three-phase.
WFMASTER
Wait from master is used in high priority units to hold back reclosing of the low
priority unit during sequential reclosing.
Other outputs
The other outputs can be connected for indication, disturbance recording and so on as
required.
10.3.3.3 STBRREC- Auto-recloser parameter settings
Auto-recloser parameter settings
Operation
The operation of the Autorecloser for 1/3-phase operation (STBRREC, 79) function
can be switched
On and Off . The setting makes it possible to switch it On or Off using
an external switch via IO or communication ports.
NoOfShots, Number of reclosing shots
In power transmission 1 shot is mostly used. In most cases one reclosing shot is
sufficient as the majority of arcing faults will cease after the first reclosing shot. In
power systems with many other types of faults caused by other phenomena, for
example wind, a greater number of reclose attempts (shots) can be motivated.
First shot and reclosing program
There are six different possibilities in the selection of reclosing programs. What type
of reclosing to use for the different kinds of faults depends on the power system
configuration and on the users practices and preferences. When the circuit-breakers
only have three-phase operation, then three-phase reclosing has to be chosen. This is
usually the case in subtransmission and distribution lines. Three-phase tripping and
reclosing for all types of faults is also widely accepted in completely meshed power
systems. In transmission systems with few parallel circuits, single-phase reclosing for
single-phase faults is an attractive alternative for maintaining service and system
stability.
Auto-reclosing open times, dead times
Three-phase shot 1 delay: For three-phase High-Speed Auto-Reclosing (HSAR) a
typical open time is 400 ms. Different local phenomena, such as moisture, salt,
pollution etc. can influence the required dead time. Some users apply Delayed Auto-
Reclosing (DAR) with delays of 10 s or more. The delay of reclosing shot 2 and
possible later shots are usually set at 30 s or more. A check that the CB duty cycle can
manage the selected setting must be done. The setting can in some cases be restricted
1MRK 505 291-UEN A
Section 10
Control
225
Application manual