Irig-B - GE 845 Instruction Manual

CHAPTER 2: INSTALLATION

IRIG-B

845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
wired with all the positive (+) terminals connected together and all the negative (–)
terminals connected together. Each relay must be daisy-chained to the next one. Avoid
star or stub connected configurations. The last device at each end of the daisy-chain
should be terminated with a 120 ohm ¼ watt resistor in series with a 1 nF capacitor across
the positive and negative terminals. Observing these guidelines ensure a reliable
communication system immune to system transients.
IRIG-B is a standard time code format that allows time stamping of events to be
synchronized among connected devices within 1 millisecond. The IRIG time code formats
are serial, width-modulated codes which can be either DC level shift or amplitude
modulated (AM) form. The type of form is auto-detected by the 845 relay. Third party
equipment is available for generating the IRIG-B signal; this equipment may use a GPS
satellite system to obtain the time reference so that devices at different geographic
locations can also be synchronized.
Figure 2-27: IRIG-B connection
ELECTRICAL INSTALLATION
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