Network design

Consulting – Engineer Specification | Ethernet network design issues in the substation

A number of developments mean that the consulting specification engineer will have to solve a myriad of issues related to the use of Ethernet in a substation.

More and more products include Ethernet, which as you probably know is an IEEE standard (IEEE 802.3) suite comprising the “seven-layer model” in communications created by ISO, or the International Organization for Standardization.

Intelligent Electronic Devices (IEDs) include Ethernet for communications between them. If the CSE is working on an IEC 61850 implementation, it is Ethernet-based. It would be very common for the monitoring and control of this substation to be tied to the substation owner’s wide area network (WAN) or even their local area network (LAN) for, say, a large industrial facility. Gone are the days – at least they’re quickly disappearing – when we were running dedicated copper lines and serial connections. In short, the electricity industry is moving towards Ethernet connectivity in the substation.

Ethernet design for a substation must include functional and environmental factors to perform the tasks it is called upon to perform. Design considerations for Ethernet include, for example, the speed of various substation operations and message prioritization. These are critical factors, especially if this Ethernet network has protective relay functions.

One of the first things to look at is the survivability of Ethernet products like switches and routers. You can’t rush to your local big box retailer for switches and routers used in the home. Ethernet products must have the same environmental survival characteristics as other products in this substation. The IEEE standard which defines the environmental requirements for communication devices in a substation is IEEE 1613.

IEEE 1613 defines all things such as temperature range, susceptibility to surges, voltage supply, cooling, transients, anything that the device may be made to experience in the normal operation of the substation and continue to operate in the system.

Another important aspect of the network is how the network is configured. Switches and routers have configuration parameters for how they route traffic, how they route, how they learn – traffic heuristics. These are commonly referred to as managed switches and managed routers and they will work differently depending on how they are configured. Space does not allow for a digression into configuring the network for proper substation operation here, but the problem requires the CSE with no experience in this area to secure the services of a network engineer to determine how this network should. be configured.

Network management is another problem. If the substation network connects to the facility’s WAN or LAN or any other IT-related facility, the customer’s IT department will get involved. This IT department will want an SNMP compliant product and may influence the type of switch or router that is installed, due to its capabilities, management tools, etc. SNMP, or Simple Network Management Protocol, is used by and built into telecommunications products to allow remote monitoring of, for example, communication device trouble codes.

In a utility, this work often brings IT and OT (operating technology) into conflict, as they debate the characteristics, virtues, and desired functionality of IT products entering a substation environment. For the CSE, it is extremely important to understand and make understand to all the parties concerned that the Ethernet products designed in a substation, in particular as part of the protection and control system, must first meet the requirements and functionality of the protection and control system. Second, it must meet the requirements of the IT department, once the primary requirement is met. Everyone should be on board with the aircraft priorities and the equipment selection is made accordingly. A simple web search will reveal a range of products designed for substation applications.

Fortunately, the CSE has a range of choices when determining the Ethernet media in the substation; some applications may require copper, others fiber optic cable. Fiber is less sensitive to transients and surges, but unless Ethernet has a very long life to the device it serves, fiber is considered unnecessary given the current product class. . Finally, there is a question of external access. There is great value in connecting to a WAN connected to the Internet for remote access, monitoring and control. While an Ethernet network connected to the Internet offers a wide range of possibilities in terms of remote access and control, it also raises cybersecurity concerns. Thus, network design issues will include firewalls and cybersecurity standards related to those of IEEE 1686.


Sam Sciacca is an active senior member of the IEEE and the International Electrotechnical Commission (IEC) in the field of utility automation. He has over 25 years of experience in the domestic and international electric utility industry. Sciacca chairs two IEEE working groups that focus on cybersecurity for electric utilities: the C1 Substation Working Group (P1686) and the Power System Relay Committee Working Group H13. (PC37.240). Sciacca is also chairman of SCS Council.


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