Autoreclose Sequences; Figure 4.1-1 Typical Autoreclose Sequence With 3 Instantaneous And 1 Delayed Trip - Siemens 7SR224 Technical Manual

4.1.2

Autoreclose sequences

The CONTROL & LOGIC>AUTORECLOSE PROT'N and CONTROL & LOGIC>AUTORECLOSE CONFIG'
menus, allow the user to set independent Protection and Autoreclose sequences for each type of fault i.e. Phase
Fault (P/F), Earth Fault (E/F), Sensitive Earth Fault (SEF) or External Protections (EXTERN). Each Autoreclose
sequence can be user set for up to four-shots i.e. five trips + four reclose sequence, with independently
configurable type of Protection Trip, either Fast (Inst) or Delayed with associated Deadtime Delay time for each
shot. The user has programming options for Autoreclose Sequences up to the maximum shot count i.e.:-
Inst or Delayed Trip 1 + (DeadTime 1: 0.1s-14400s)
+ Inst or Delayed Trip 2 + (DeadTime 2: 0.1s-14400s)
+ Inst or Delayed Trip 3 + (DeadTime 3: 0.1s-14400s)
+ Inst or Delayed Trip 4 + (DeadTime 4: 0.1s-14400s)
+ Inst or Delayed Trip 5 – Lockout.
The AR function recognizes developing faults and, as the shot count advances, automatically applies the correct
type of Protection Trip and associated Dead time for that fault-type at that point in the sequence.
A typical sequence would consist of two Inst trips followed by at least one combined Delayed + HighSet (HS)
Trip. This sequence enables transient faults to be cleared quickly by the Inst trip(s) and permanent fault to be
cleared by the combined Delayed trip. The delayed trip must be 'graded' with other Recloser/CB's to ensure
system discrimination is maintained, i.e. that as much of the system as possible is live after the fault is cleared.
A HS trips to lockout setting is provided such that when the number of operations of elements assigned as HS
trips reach the setting the relay will go to lockout.
The number of Shots (Closes) is user programmable, note: - only one Shot Counter is used to advance the
sequence, the Controller selects the next Protection characteristic/Dead time according to the type of the last Trip
in the sequence e.g. PF, EF, SEF or EXTERNAL.
Reclose Dead Time
User programmable dead times are available for each protection trip operation.
The dead time is initiated when the trip output contact reset, the pickup is reset and the CB is open. Additionally, .
if check synchronising feature is included, the line or bus voltage must be detected as dead, unless the Live Line
Check setting in the Autoreclose Config menu is set to disabled.
The CB close output relay is energised after the dead time has elapsed.
st nd
1 Trip (Inst) 2
st
1 Dead Time

Figure 4.1-1 Typical Autoreclose Sequence with 3 Instantaneous and 1 Delayed trip

©2010 Siemens Protection Devices Limited
rd
3 Trip (Inst)
Trip (Inst)
nd
rd
2 Dead Time
3 Dead Time
7SR224 Argus Description of Operation
th
4 Trip (Delayed)
th
4 Dead Time
Chapter 1 Page 41 of 70