3-28 G60 Generator Protection System GE Multilin
3.2 WIRING 3 HARDWARE
3
3.2.10 IRIG-B
IRIG-B is a standard time code format that allows stamping of events to be synchronized among connected devices. The
IRIG-B code allows time accuracies of up to 100 ns. Using the IRIG-B input, the G60 operates an internal oscillator with 1
µs resolution and accuracy. The IRIG time code formats are serial, width-modulated codes that can be either DC level
shifted or amplitude modulated (AM). Third party equipment is available for generating the IRIG-B signal; this equipment
can use a GPS satellite system to obtain the time reference so that devices at different geographic locations can be syn-
chronized.
Figure 3–28: OPTIONS FOR THE IRIG-B CONNECTION
Using an amplitude modulated receiver causes errors up to 1 ms in event time-stamping.
When IRIG-B is used as the time synchronization source for synchrophasors, the DC level shifted option must be
used in order to achieve the 1% Total Vector Error specified by the standard. If amplitude modulated IRIG-B is
used, it results in a 20 to 25 degree error in the synchrophasor angle measurement. The IEEE 1588 Precision Time
Protocol can also be used to achieve accurate time synchronization for synchrophasor calculation.
UR-series device
BNC (in)
Receiver
RG58/59 coaxial cable
GPS satellite system
GPS connection
IRIG-B (–)
4A
+
827756A8.CDR
IRIG-B
time code generator
(DC-shift or
amplitude modulated
signal can be used)
4B
IRIG-B (+)
UR-series device
BNC (in)
Receiver
Twisted-pair cable
GPS satellite system
GPS connection
IRIG-B (–)
4A
+
IRIG-B
time code generator
(DC-shift or
amplitude modulated
signal can be used)
4B
IRIG-B (+)