The GE Multilin HardFiber system carries the process bus with yard units called Bricks, prefabricated outdoor fiber cables, a passive cross connect panel in the control house and a process card in the UR relay. Each Brick sends samples and statuses and receives commands over point-to-point links, with no switches and no configuration in the yard.
What HardFiber is
Short answer. HardFiber is GE Multilin’s IEC 61850 process bus solution. It replaces the copper cables between the yard and the control house with prefabricated outdoor fiber cables that connect yard units (Bricks) to relays of the Universal Relay (UR) family. It is a specific case of a process bus: there is no switched network in between.
The four components
- Brick. Hardened yard unit. All the copper of a primary device ends in it: current, voltage, statuses and control outputs. The catalog specifies it for outdoor installation with IP66 rating and a temperature range of -40 °C to 85 °C.
- Outdoor fiber cable. Delivered cut to length and pre-terminated, with the DC power cabling included, so there are no fiber splices or terminations on site. It runs in trays, ducts or direct burial.
- Cross connect panel. Installed in a rack in the control house. It is passive: it has no firmware, settings or maintenance. The assignment between Bricks and relays is made with fiber patch cords: hence “hard fiber”.
- UR process card. The relay’s communication interface; it serves up to eight Bricks.
Each Brick transmits its measurements and receives commands from up to four protection and control devices, over dedicated point-to-point links.
- Primary equipment. Current and voltage transformers and contacts end at the Brick
- Brick in the yard. Digitizes and publishes samples and statuses
- Outdoor fiber cable. Pre-terminated, point to point
- Cross connect panel. A fiber cord assigns the Brick to each relay
- UR process card. The relay receives samples and GOOSE and sends commands
What it communicates
According to the manufacturer’s catalog, the system uses IEC 61850-9-2 for samples, IEC 61850-8-1 for GOOSE and bidirectional single-fiber 100Base-BX Ethernet channels. Since each link is dedicated and point to point, there is no shared network between the Brick and the relay.
What each Brick measures and operates
The catalog’s technical data make it possible to size the scope of a Brick:
- Current: 1 A or 5 A CT secondary and nominal frequency from 20 to 65 Hz.
- Voltage: VT secondary from 50 to 240 V.
- Contact inputs: 18.
- Universal DC inputs: 3, which accept RTD, potentiometer, voltage or milliamps.
- Outputs: 4 solid-state relays with operate and release time under 100 µs.
- Power supply: 110 to 250 V DC, or 100 to 240 V AC.
What changes on site and in maintenance
- Less copper and fewer terminations between the yard and the control house. Copper cables run only from the primary device to the Brick.
- Simple replacement. The Brick is swapped without redoing the copper wiring, because everything ends in connectors designed to prevent wrong connections (MIL-STD-38999 connectors).
- Duplicated Bricks. A second Brick acquires each signal again, which increases protection reliability.
- Self-diagnostics. Each Brick monitors dozens of internal subsystems and reports several times per second.
- Incremental expansion. A dedicated digital core for each relay inside the Brick makes it possible to add or modify one application without touching the others.
This reduces wiring hours on site, but it moves verification to other points: the fiber assignment in the panel, the process card configuration and end-to-end tests with the Brick.
What to test
- Each fiber in the cross connect panel corresponds to the intended Brick and relay.
- Brick current and voltage measurements against primary or secondary injection, with the correct polarity.
- Statuses and control outputs: open and close from the relay to the primary device.
- Behavior on loss of a Brick or a link.
For general context see merging unit and lost sampled values on the process bus.
Process bus with Tiza Group
Are you going to receive or commission a process bus with Bricks and UR relays? At Tiza Group we verify signal assignment and run end-to-end tests; we also configure the relays through our remote relay configuration.
Related guides
- Process bus
- Merging unit
- Lost sampled values on the process bus
- GE Multilin UR relay for feeders
- GE Multilin T60 and T35 relay
- GE EnerVista UR Setup, 8 Series Setup and Launchpad software
- PRP and HSR (IEC 62439-3)
References
- GE Multilin, catalog “HardFiber: IEC 61850 Process Bus Solution”.
- IEC 61850-9-2 (samples) and IEC 61850-8-1 (GOOSE).
Frequently asked questions
How does HardFiber differ from other merging units?
HardFiber is not a generic merging unit: it is a closed, single-manufacturer architecture, with the Brick in the yard, the process card in the UR relay and point-to-point links. It uses IEC 61850-9-2 for samples and 8-1 for GOOSE, but signals are assigned with fiber and panels, not with a switched network.
What happens if a Brick fails?
The Brick can be duplicated so that each signal is acquired twice, which increases reliability. Since all copper wiring ends at the Brick, replacing it comes down to swapping it and reconnecting the connectors.
Is a process bus with Bricks tested differently?
Yes. The copper wiring between yard and control house disappears, but injection and signal verification are done against the Brick, and the assignment of each fiber in the cross connect panel must be checked.