ABB Relion 670 Series RES670, Technical Manual

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21.2.14 GPS time synchronization module (GTM)
21.2.14.1 Introduction
This module includes a GPS receiver used for time synchronization. The GPS has one
SMA contact for connection to an antenna. It also includes an optical PPS ST-connector
output.
21.2.14.2 Design
The GTM is a PCMIP-format card and is placed only on one of the ADM slots. The
antenna input connector is shielded and directly attached to a grounded plate to eliminate
the risk of electromagnetic interference.
All communication between the GCM and the NUM is via the PCI-bus. PPS time data is
sent from the GCM to the rest of the time system to provide 1μs accuracy at sampling
level. An optical transmitter for PPS output is available for time synchronization of
another relay with an optical PPS input. The PPS output connector is of ST-type for
multimode fibre and could be used up to 1 km.
21.2.14.3 Monitored data
Table 673: SYNCHGPS Monitored data
Name Type Values (Range) Unit Description
NoOfSatellites INTEGER - - Number of GPS signals from
satellites
21.2.14.4 Technical data
Table 674: GPS time synchronization module (GTM)
Function Range or value Accuracy
Receiver – ±1µs relative UTC
Time to reliable time reference with antenna in new
position or after power loss longer than 1 month
<30 minutes –
Time to reliable time reference after a power loss longer
than 48 hours
<15 minutes –
Time to reliable time reference after a power loss shorter
than 48 hours
<5 minutes –
1MRK 511 365-UUS A
Section 21
IED hardware
Phasor measurement unit RES670 2.1 ANSI 799
Technical manual