CHAPTER 3: INSTALLATION
DIRECT INPUT AND OUTPUT COMMUNICATIONS
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL
3-39
3
•
Flashing yellow — internal mode while receiving a valid data packet
•
Solid red — (switch to) internal timing mode while not receiving a valid data packet
The link/activity LED status is as follows:
•
Flashing green — FPGA is receiving a valid data packet
•
Solid yellow — FPGA is receiving a "yellow bit" and remains yellow for each "yellow bit"
•
Solid red — FPGA is not receiving a valid packet or the packet received is invalid
3.4.9 C37.94SM interface
The UR-series C37.94SM communication modules (2A and 2B) are designed to interface with modified IEEE C37.94
compliant digital multiplexers or IEEE C37.94 compliant interface converters that have been converted from 820 nm multi-
mode fiber optics to 1300 nm ELED single-mode fiber optics. The IEEE C37.94 standard defines a point-to-point optical link
for synchronous data between a multiplexer and a teleprotection device. This data is typically 64 kbps, but the standard
provides for speeds up to 64
n
kbps, where
n
= 1, 2,…, 12. The UR-series C37.94SM communication module is 64 kbps only
with
n
fixed at 1. The frame is a valid International Telecommunications Union (ITU-T) recommended G.704 pattern from
the standpoint of framing and data rate. The frame is 256 bits and is repeated at a frame rate of 8000 Hz, with a resultant
bit rate of 2048 kbps.
The specifications for the module are as follows:
•
Emulated IEEE standard — Emulates C37.94 for 1
×
64 kbps optical fiber interface (modules set to
n
= 1 or 64 kbps)
•
Fiber optic cable type — 9/125
μ
m core diameter optical fiber
•
Fiber optic mode — Single-mode, ELED compatible with HP HFBR-1315T transmitter and HP HFBR-2316T receiver
•
Fiber optic cable length — Up to 11.4 km
•
Fiber optic connector — Type ST
•
Wavelength — 1300 ±40 nm
•
Connection — As per all fiber optic connections, a Tx to Rx connection is required
The UR-series C37.94SM communication module can be connected directly to any compliant digital multiplexer that
supports C37.94SM, as shown.
It also can be connected directly to any other UR-series relay with a C37.94SM module, as shown.
In 2008, GE Digital Energy released revised modules 2A and 2B for C37.94SM communication to enable multi-ended fault
location functionality with firmware 5.60 release and higher. All modules 2A and 2B shipped since the change support this
feature and are fully backward compatible with firmware releases below 5.60. For customers using firmware release 5.60
and higher, the module can be identified with "Rev D" printed on the module and is to be used on all ends of L60
communication for two and three terminal applications. Failure to use it at all ends results in intermittent communication
UR-series
device
C37.94SM
fiber interface
up to 10 km
842757A2.CDR
Digital
multiplexer
C97.94SM
UR-series
device with
C37.94SM
module
C37.94SM
fiber interface
up to 10 km
UR-series
device with
C37.94SM
module
842758A2.CDR
