Auto Reclose Sequences; Figure 4.1.2-1 Typical Sequence With 3 Instantaneous And 1 Delayed Trip - Siemens 7SR18 Solkor Manual

4.1.2

Auto Reclose sequences

The CONTROL & LOGIC>AUTO RECLOSE PROT'N and CONTROL & LOGIC>AUTORECLOSE CONFIG'
menus, allow the user to set independent Protection and Auto Reclose sequences for each type of fault i.e. Phase
Fault (P/F), Derived/Measured Earth Fault (E/F) or External Protections (EXTERN). Each Auto Reclose sequence
can be user set to up to four-shots i.e. five trips + four reclose sequence, with independently configurable type of
Protection Trip. Overcurrent and earth fault elements can be assigned to any combination of Fast (Inst), Delayed
or highset (HS) trips. Deadtime Delay time settings are independent for each AR shot. The user has
programming options for Auto Reclose 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 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 Delayed 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, ie. 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 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.
The CB close output relay is energised after the dead time has elapsed.
st
1 Trip (Inst)
st
1 Dead Time
Figure 4.1.2-1
Unrestricted ©2018 Siemens Protection Devices Limited
rd
nd
3 Trip (Inst)
2 Trip (Inst)
nd
2 Dead Time
3
Typical Sequence with 3 Instantaneous and 1 Delayed trip
th
4 Trip (Delayed)
rd
th
Dead Time
4
7SR18 Description Of Operation
Dead Time
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