IEC 61850 is the backbone for the Smart Power Automation and Control Systems (PACs). IEC 61850 standardizes the data model, the multiple communication services, the system configuration description language (SCL) and even the link layer for the networking and for synchronization. An intensive effort of the IEC 61850 community and industry has been developed to provide a zero-delay and no frame lost Ethernet based networking solution for critical control messages communicated within these systems (like GOOSE or SMV messages).

IEC 61850 adopts IEC 61439-3 clauses 4 and 5 to provide bump-less Ethernet redundancy in PACs. IEC 61439-3 Clause 5 is named High-availability Seamless Redundancy (HSR) and clause 4, Parallel Redundancy Protocol (PRP).

Both protocols offer zero switch-over delay time, no-frames lost in case of failure, and strong means for Network Supervision at Layer 2.

HSR provides redundancy by sending packets in both directions through a ring network and discarding the duplicated one on HSR capable reception node. In case of an interruption in the ring, the frame will always be received through the other port.

PRP adapted nodes are connected to two independent Ethernet networks and send the frame over both networks. This grants the reception of the frame through when any of the network fails.

Diagrama_130206

- Network Communications in Power Substation using HSR and PRP -

The figure above shows an example of this new protocols implemented in the automation for a Power Substation. While HSR interconnects Intelligent Electronic Devices (IEDs) in each bay (Intra-Bay communications), PRP is suitable to be used for Station and Inter-Bay Buses, attaching many heterogeneous devices.

As can be depicted in this example, in order to maintain redundancy in the communications, the interconnection between PRP and HSR networks is performed using redundant gateways. Each HSR link is connected to each PRP LAN using two gateway devices. Thus, a potential ‘Single-Point-of-Failure’ is avoided.

As it has shown in this scenario, the combination of industrial protocols is increasing in complexity and variety. The need for flexibility of these emerging Ethernet based protocols makes FPGA and reconfigurable devices in general, the best candidates to implement network devices able to combine multiple protocols. FPGAs,  powered by the proper IP Core  provide:

  • Hardware processing capabilities to achieve low switching latency times
  • Flexibility enough to adapt the design to specific customer requirements
  • Protocol updates supported by hardware and complex combinations (eg. HSR and IEEE 1588)

Since 2011, SoC-e is providing these technologies to companies of the Electric Sector that have integrated SoC-e IPs and modules in IEDs, Merging Units, RTUs and in many other equipment. Among other products, the following SoC-e products target the Electric Sector: