Siemens 7SR51 - 7.2 52 Circuit-Breaker Control

52 Circuit-Breaker Control
Overview of Function
The CB control function is used to configure:
•
CB open/close control and monitoring of the CB open/close status
•
CB operations (maintenance) counters and alarm targets
•
CB wear (I
2
t) counters and alarm targets
Structure of the Function
The CB control function element has group dependent settings. These settings can be different in each
settings group – group numbers (Gn) 1 to 4.
This function corresponds to the logical node Q0XCBR* in IEC 61850.
The CB control and monitoring function is configured in 3 stages:
•
The CB control and status monitoring parameters are defined
•
CB operations counters and counter target settings are entered
•
Parameters to define the CB wear (I
2
t) monitoring are entered
A Manual Close command can be initiated in one of 3 ways:
•
Via a Close CB binary input
•
Via the data communication channel(s)
•
From the relay Control Mode menu
It causes an instantaneous operation via Manual Close CB binary output, over-riding any DAR sequence in
progress.
Repeated manual closes are avoided by checking for positive edge triggers. Even if the Manual Close input
is constantly energized the relay will only attempt 1 close.
A Manual Close will initiate switch-onto-fault protection if 50SOTF is enabled. If a fault appears on the line
during the Close Pulse or during the Reclaim Time with Line Check enabled, the relay will initiate a
trip and Lock-out. This prevents a CB being repeatedly closed onto a faulted line. Where Line Check
Trip = Delayed then instantaneous protection is inhibited until the reclaim time has elapsed.
Manual Close resets Lockout, if the conditions that caused Lockout have reset, i.e. there is no trip or
Lockout input present.
Manual Close cannot proceed if there is a Lockout input present.
With the autoreclose function set to Disabled the Manual Close control is still active.
The I
2
t counter can provide an estimation of contact wear and maintenance requirements. The algorithm
works on a per phase basis, measuring the arcing current during faults. The I
2
t value at the time of trip is
added to the previously stored value and an alarm is given when any 1 of the 3 phase running counts exceeds
the set alarm limit . The t value is the time between CB contacts separation when an arc is formed, Separa-
tion Time, and the CB Clearance time.
The I
2
t value can also triggered and reset from a binary input or command.
7.2
7.2.1
7.2.2
Control Functions
7.2 52 Circuit-Breaker Control
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 409
C53000-G7040-C014-1, Edition 11.2019