Appendix A - Cross Triggering - Novatech Bitronics M87X Series Manual

APPENDIX A - CROSS TRIGGERING

Cross-Triggering
There are many possible uses for the Input / Output functions available from 70 Series
Recorders, but Cross-Triggering deserves special attention since it is prerequisite to the
application of distributed recording.
Intelligent Electronic Devices (IEDs) like microprocessor-based relays or 70 Series
Recorders are generally used to measure the electrical parameters associated with a
particular load, such as a feeder for example. In contrast, most dedicated Sequence-of-
Events (SOE) Recorders or Digital Fault Recorders (DFRs) collect measurements from all
points of interest throughout an entire substation or load center. Those devices generally
produce recordings that include the activity of all points in a single document facilitating
analysis by showing everything on a common time scale. A consolidated document like
that can be produced by time-synchronized distributed IEDs by combining files captured by
each of the recorders.
In order to consolidate all the recordings from IEDs distributed throughout a substation, all
the IEDs must first be made to trigger simultaneously whenever an event of interest is
sensed by any one unit in the substation. That mechanism is referred to as Cross-
Triggering. Recordings are then downloaded and combined by software designed for that
purpose (described elsewhere). This appendix will concentrate on methods available for
cross-triggering distributed IEDs.
70 Series Recorders support two mechanisms for cross-triggering one another. These
mechanisms are vendor-independent so may be used in combination with protective relays
and other IEDs to the extent that status and control points are available or that protocols
are supported by the other devices.
1. Hard-wired, using discrete digital I/O. Contacts wired in parallel on a dedicated
cable pass a voltage signal to the status inputs on each IED when an event is sensed.
The status input on each device can then be configured to trigger a recording.
2. Ethernet:
a. using GOOSE. Status points are communicated across an Ethernet LAN using the
IEC-61850 standard. The principal advantage of GOOSE messaging is that it does
not require a separate dedicated control cable for physical contacts.
b. using GSSE. Status points are communicated across an Ethernet LAN. The
principal advantages of GSSE are interoperability with legacy equipment and
simplicity of configuration. All 70 Series firmware released from April 2004 to June
2008 supported UCA. The term "GOOSE" when used in the UCA context is
equivalent to GSSE as defined by IEC-61850. GSSE messaging can be set up with
the 70 Series Configurator alone. The IED Configurator is not required for GSSE.
The 70 Series Recorder provides considerable flexibility in how a user could customize
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