Extended Protective Relaying
35
7 Extended Protective Relaying
7.1
Overview
The SB Energy-Comm trip unit offers several protective relay-
ing functions beyond the standard trip unit functionality. These
extended functions include types of current, voltage, and fre-
quency protection usually associated with a protective relay.
•
Neutral Overcurrent
•
Current Unbalance
•
Undervoltage
•
Voltage Unbalance
•
Over Voltage
•
Reverse Power
•
Over Frequency
•
Under Frequency
Exceeding the configured setpoint (limit) will result in the fol-
lowing actions by the trip unit:
If set to trip and alarm:
•
Trip the circuit breaker
•
Store a record of the event in the trip log including the time
and date of the trip
•
Close the optional breaker relay output contact, which may
be connected to a visible or audible alarm (or both)
•
Communicate with any supervisory device that a trip con-
dition was reached
If set to alarm only:
•
close the relay output contact, which may be connected to
a visible or audible alarm (or both)
•
Store a record of the event in the event log including the
time and date of the alarm
•
Communicate with any supervisory device that an alarm
condition was reached
To find settings for the protective relay functions:
1.
From the
Main Menu
, select
Protective Functions
.
2.
From the
Protective Menu
, select
Protective Relays
.
For each protection type, users may choose that the trip unit
either alarms, or trips and alarms, when these parameters
exceed a set value.
7.2
Tripping and Alarming
For the protective relaying functions, users may either alarm on
the function, or both trip and alarm on the function. You cannot
trip without alarming. In the examples below, the first case
shows no alarm or trip; the second shows the alarm set, and
the third shows both trip and alarm set.
To activate this function:
1.
Press the Up Arrow key
when either the alarm or the
trip checkbox is highlighted.
2.
If you select tripping, the alarm checkbox is automatically
highlighted as well.
