Chapter 1) 7SR242 Duobias Description Of Operation
©2015 Siemens Protection Devices Limited
Chapter 1 Page 54 of 60
6.3 Maintenance
6.3.1 Output Matrix Test
The feature is available from the Relay fascia and allows the user to operate binary outputs or LEDs assigned to
relay functions.
Any protection function which is enabled in the setting menu will appear in the Output Matrix Test.
6.3.2 CB Counters
Four CB trip counters are provided:
CB1 Total Trip Count:
Increments on each trip command issued.
CB1 Delta Trip Count:
Additional counter which can be reset independently of the
Total Trip Counter. This can be used, for example, for
recording trip operations between visits to a substation.
CB2 Total Trip Count
As CB1
CB2 Delta Trip Count:
As CB1
The status of each counter can be viewed in the INSTRUMENTS mode.
Binary outputs can be mapped to each of the above counters, these outputs are energised when the
user defined
Count Target
is reached.
6.3.3 I
2
t CB Wear
CB1 and CB2 wear counters are also provided:
I
2
t CB1 Wear:
Provides an estimate 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 one of the three phase running
counts exceeds the set
Alarm limit
. The t value is the time
between CB contacts separation when an arc is formed,
Separation Time,
and the CB
Clearance time
.
I
2
t CB2 Wear:
As CB1
The status of each counter can be viewed in the INSTRUMENTS mode.
Binary outputs can be mapped to each of the above counters, these outputs are energised when the
user defined
Alarm Limit
is reached.
Summary of Contents for 7SR242 Duobias
Page 1: ...Answers for energy 7SR242 Duobias Transformer Protection Relay Reyrolle Protection Devices ...
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