Hubbel RFL PLC Hybrid Pro, User Manual

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RF-MCHYBRIDPRO-01
Hubbell Power Systems, Inc. – RFL™ Products
June 2019 26 973.334.3100
One example application might be where a transmission line is to be split, and a new station will be
constructed the in the middle of the line (for example, a series capacitor site). There are existing
protection signals over PLC at Station A and Station C, which must be preserved. Also, new protection
signals must be inserted at Station B. Instead of using a re-keying scheme to send the signals from A to
C, through B (which would add significant cost while significantly reducing the reliability of the
protection channel), a bypass hybrid can be installed, negating the need for a re-keying scheme or a re-
design of the protection scheme. Protection signals from the new station can be sent to both remote
stations. The cost for all the functionality is approximately 6.5 dB loss on the channel in any direction.
Another application is using a 3-terminal protection scheme on a linear transmission network. The
bypass hybrid allows any one station to reach any of two others, as in a 3-terminal ring. Unique
protection schemes can be designed which incorporate this multi-station communication ability.
BAL
to/from
Line Tuner B
BAL
To/from local
transmitters/receivers
BAL
to/from
Line Tuner A
Figure 29 – Bypass Hybrid, Functional Schematic
The RFL™ PLC Hybrid Pro bypass hybrid is functionally the same as the circuit shown in
F
IGURE
29 .
However, the RFL™ PLC Hybrid Pro has implemented this circuit and its interconnections on a single
board, taking the number of connections which must be made from 9 down to 3. This dramatically
reduces the complexity of this application and so minimizes opportunities for error or improper
connections., during both commissioning and maintenance work.
The LINE ports of the bypass hybrid each have a gas discharge tube (E1, E2) and slo-blo fuse (F1, F2)
for overvoltage and overcurrent protection.
Table 7 – Bypass Hybrid Specifications
Splitter/Combiner Specifications
Impedance (each port)
50 ohms (75 ohms available by request)
Insertion loss approximately 6.5 dB
Power Rating 10 Watts, each port