Rugged communications for distribution automation

One of the important functions of distribution automation is called FDIR (fault detection, isolation, and restoration). It detects faulty segment in a distribution line then isolates the fault by performing topology changes in the distribution grid (opening and closing specific circuit breakers) – and finally restoring the initial topology once it is confirmed that the faulty condition has been eliminated. In the pre-digital era, when a fault occurred on a feeder, a repair crew had to be dispatched to the field and manually open and close circuit breakers to restore the grid. It could take up to several hours to complete the operation. In modern digital grids, it is expected that an automated FDIR algorithm will detect and isolate the faulty segment within 100 milliseconds or less. Such performance is possible with the use of a distributed architecture with Intelligent Electronic Devices (IEDs) using communications to exchange their status via IEC 61850 fast GOOSE messaging. There are many examples in the world where Siemens industrial wireless communications, both public LTE and private broadband wireless, helped to achieve the self-healing grid.

In large-scale deployments, it is very important to avoid making decisions based exclusively on the initial price of the solution (CAPEX). A more appropriate selection is made by taking into account total cost of ownership, and this always includes OPEX. In order to minimize OPEX, and therefore optimize the total cost of ownership, the solution should incorporate robust industrial-grade solutions that will operate reliably in adverse conditions for many years without needing repairs or replacements. Selecting solutions that exceed industry standards and feature long product lifecycles and high MTBF values (mean time between failures) is one way to protect your ROI.

Depending on the geographical region and population density, there may not be a fiber-optic or similar wired telecommunications infrastructure to interconnect devices in the secondary distribution grid. Wireless communications are a natural choice in this case, however, there is a broad range of wireless technologies to choose from. It is obvious there is no “one solution fits all” in terms of wireless communications. Depending on economic and technical criteria, a choice has to be made between private wireless networks and public cellular networks. Private wireless communications like 4G private broadband offer greater reliability, high security, and OPEX optimization, while public cellular networks are attractive because of lower CAPEX, faster deployments and good coverage in most areas. What is clear, however, is that the solution should be standard based, interoperable, scalable and support multi-service network infrastructure.

When designing the network for distribution automation, it is important to look closely at the requirements of the different applications that will use the communications architecture. The requirements should include:

• the number of nodes to be supported
• type of communications interfaces (like Ethernet, RS-232 serial) 
• required reliability 
• necessary data bandwidth 
• maximum tolerated latency 
• network redundancy options 
• time synchronization protocols 
• need to support multicast traffic 
• need to restrict data flows to specific locations or devices
• monitoring and self-diagnostic requirements.

In order to ensure scalability, the solutions shall include a powerful set of Layer 2 and Layer 3 communications protocols. Siemens Professional Services certified networking experts can assist during the design, engineering and commissioning phases. Additionally, Siemens offers a broad range of certification trainings for industrial communications.

For more on Professional Services for Industrial Networks, click here

More and more utilities are developing strategies for migrating their applications to the latest IT architectures that use edge or cloud computing. Cloud platforms create opportunities for ubiquitous connectivity to assets, data analytics, improved monitoring, predictive maintenance, and more. A big advantage of a cloud-based system is increased competitiveness thanks to a rich ecosystem of applications and services that allow the use of new business models. Those systems should be based on standardized open IoT protocols to avoid vendor lock-in. In addition, edge computing gives companies the ability to move intelligence and data processing closer to the field and process levels. Both cloud and edge increase flexibility and scalability by facilitating easy service provision. Modern communications multi-service platforms such as RUGGEDCOM RX1400 with Virtual Processing Engine (VPE) or RUGGEDCOM RX1500 family with APE1808 are examples of Smart Communications Nodes with edge computing capabilities and cloud connectivity. They are a powerful solution, ideal for running third-party applications.

Learn more about the application processing engine RUGGEDCOM APE1808

Learn more about the multi-protocol intelligent node RUGGEDCOM VPE1400