Fault indication and, Cross triggering, Fault indication and cross – SATEC PM180 Operation Manual User Manual
Page 108: Triggering
Chapter 8 Configuring Recorders
Configuring the Fault Recorder
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PM180 Substation Automation Unit
them, adjust the thresholds according to your network conditions before enabling
triggers.
The Current Unbalance trigger has a different calculation algorithm than the
common current unbalance measurements. Since the unbalance readings give a
relation of the maximum deviation from the average to the phase average current,
the value could produce high readings for low currents and may not be used as a
fault trigger. The Current Unbalance trigger used with the Fault recorder shows a
relation to the CT rated current instead of the three-phase average and is not
sensitive to low currents.
Configuring Digital Triggers
If you use external triggering of the Fault recorder through digital inputs, you should
individually link each digital input to the Fault recorder (see
in Chapter 7). The external triggering is enabled for the Fault recorder by default and
cannot be disabled by the user.
Fault Indication and Cross Triggering
When the Fault recorder is triggered either by the fault detector or through digital
inputs, it generates a number of specific internal events that can be monitored
through the control setpoints to give a fault indication via relay contacts. The
following describes fault events produced by the Fault recorder:
1. FAULT DETECTED - the fault detector has detected a fault event
using the device's own measurements
2. EXTERNAL TRIGGER - the Fault recorder has been launched by
an external trigger through one of the digital inputs
3. FAULT EVENT - the Fault recorder has been launched either by
its own fault detector, or by an external trigger
These events can be found under the STATIC EVENTS group in the setpoint trigger
list (STATIC in this context means that an event is asserted all the time while its fault
condition exists).
The FAULT DETECTED event can be effectively used for cross triggering multiple
fault recorders to simultaneously record fault data at different locations when one of
the devices detects a fault. Each device should have a setpoint programmed to close
relay contacts on the FAULT DETECTED event, and one digital input linked to the
Fault recorder.
To provide cross triggering, the triggering digital inputs of all devices should be tied
together and connected to the normally opened relay contacts that indicate a fault.
To avoid self-triggering through its own digital input for the device that indicates a
fault, it is recommended to use a Form C relay and to connect the digital input
through the normally closed contacts. Thus, the device that indicates a fault
disconnects its digital input before giving a fault out.