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7SR158 Technical Manual
Control & Logic Functions
Section 4:
4.1
Manual CB Control
Functionality is provided to allow a Relay to manually Open and Close its associated Circuit-Breaker (CB).
A Manual Open Command can be initiated in one of three ways: via a Open CB binary input, via the data
communication Channel(s) or from the relay CONTROL MODE menu. It causes an instantaneous operation via
the Open CB binary output.
It should be noted that a CB Open initiated in this way is fundamentally different from a CB Trip initiated by a
protection function. A CB Trip will initiate functionality such as fault data storage and operation counter.
A Manual Close Command can be initiated in one of three ways: via a Close CB binary input, via the data
communication Channel(s) or from the relay CONTROL MODE menu. It causes an instantaneous operation via
the Close CB binary output.
Repeated Manual Closes are avoided by checking for Positive edge triggers. Even if the Manual Close input is
constantly energised the relay will only attempt one close.
Close CB Delay
Operation of the Close CB binary output can be delayed by the Close CB Delay setting. The status of this delay
is displayed on the relay fascia as it decrements towards zero. Only when the delay reaches zero will the close
command be issued and related functionality initiated.
Blocked Close Delay
The close command may be delayed for the duration that a Block Close CB signal is applied to a binary input.
This can be used, for example, to delay CB closure until the CB energy has reached an acceptable level. The
output Close CB Blocked indicates this condition.
Open CB Delay
Operation of the Open CB binary output can be delayed by the Open CB Delay setting. The status of this delay
is displayed on the relay fascia as it decrements towards zero. Only when the delay reaches zero will the close
command be issued and related functionality initiated.
CB Controls Latched
CB controls for manually closing and tripping can be latched for extra security.
With Reset operation, the control resets when the binary input drops off. This can lead to multiple control restarts
due to bounce on the binary input signal.
With Latch operation, the close or trip sequence always continues to completion (or sequence failure) and bounce
on the binary input is ignored.
Reset operation can be useful, however, as it allows a close or trip sequence to be aborted by dropping off the
binary input signal.
Chapter 1) Page 28 of 38
©2014 Siemens Protection Devices Limited
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