Oscillation Suppression; Binary Outputs; Power Output Contacts - ABB RELION SMU615 Technical Manual

1MRS758407 C
3.8.3

Oscillation suppression

Oscillation suppression is used to reduce the load from the system when a binary
input starts oscillating. A binary input is regarded as oscillating if the number of
valid state changes (= number of events after filtering) during one second is equal
to or greater than the set oscillation level value. During oscillation, the binary input
is blocked (the status is invalid) and an event is generated. The state of the input
will not change when it is blocked, that is, its state depends on the condition before
blocking.
The binary input is regarded as non-oscillating if the number of valid state changes
during one second is less than the set oscillation level value minus the set oscillation
hysteresis value. Note that the oscillation hysteresis must be set lower than the
oscillation level to enable the input to be restored from oscillation. When the input
returns to a non-oscillating state, the binary input is deblocked (the status is valid)
and an event is generated.
Table 39: Oscillation parameter values
Parameter
Input osc. level
Input osc. hyst
3.9

Binary outputs

The merging unit provides a number of binary outputs used for tripping, executing
local or remote control actions of a breaker or a disconnector, and for connecting
the merging unit to external annunciation equipment for indicating, signalling and
recording.
Power output contacts are used when the current rating requirements of the
contacts are high, for example, for controlling a breaker, such as energizing the
breaker trip and closing coils.
The contacts used for external signalling, recording and indicating, the signal
outputs, need to adjust to smaller currents, but they can require a minimum current
(burden) to ensure a guaranteed operation.
The merging unit provides both power output and signal output contacts. To
guarantee proper operation, the type of the contacts used are chosen based on
the operating and reset time, continuous current rating, make and carry for short
time, breaking rate and minimum connected burden. A combination of series or
parallel contacts can also be used for special applications. When appropriate, a
signal output can also be used to energize an external trip relay, which in turn can be
confiugred to energize the breaker trip or close coils.
All contacts are freely programmable, except the internal fault output IRF.
SMU615
Technical Manual
Values
2...50 events/s
2...50 events/s
Using an external trip relay can require an external trip circuit supervision
relay.
Basic functions
Default
30 events/s
10 events/s
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