June 7, 2023
In several previous chapters we discussed the system components that make up an OT 2.0 system. In order for those systems to provide the functionality described, the software and hardware must communicate with each other over some network substrate. To support such a diverse set of applications, requiring different levels of connectivity, bandwidth and latency, many different network substrates are necessarily used. Here we briefly discuss the network aspect of OT 2.0.
Although there are many different types of networks used across the utility landscape for OT 2.0 operations, in essence there are a few that cover the majority of the OT 2.0 applications, including:
• Fiber Optic Networks
• Cellular Networks (4G,5G)
• Radio Frequency (RF) Mesh Networks
• Satellite and Microwave Networks
Fiber optic networks are commonly used for their high data transmission speeds and reliability and often used for backbone infrastructure in OT 2.0 operations. They are primarily used for:
Backhaul Connections: These connections link substations and other key points in the grid back to the central control system, allowing for real-time communication and control.
Substation Automation: These network links can be used to transmit data between the various devices within a substation, and ultimately between the substation and the central control system.
Advanced Applications: These might include real-time grid monitoring, predictive maintenance, integration of renewable energy sources, and automated grid control.
Cellular networks are often used to transmit data to and from smart grid devices. They offer broad coverage and good data rates. The emergence of 5G technology is further increasing the potential for cellular network use for real-time communication and control in the grid. Recently private 4G LTE networks have become increasingly popular for OT 2.0 grid operations and AMI. Cellular networks primary uses are:
Distribution Automation: The real-time data transmission capabilities of 4G, LTE, and especially 5G networks can enable more efficient and reliable power distribution and operation.
Smart Metering: Cellular networks are often used to connect smart meters to the grid, or backhaul data from an RF Mesh cell. Cellular is used for this purpose due to its wide coverage and data rates. 5G could offer even more potential with its higher speeds and lower latency, as more edge computing is happening in AMI 2.0 meters.
Integration of Distributed Energy Resources (DERs): These resources can be located anywhere, and cellular networks provide the breadth of connectivity needed to monitor and manage DERs.
Vehicle-to-Grid (V2G) Systems: Cellular networks can provide the connectivity needed for these systems, allowing EVs to communicate with the grid and potentially feed power back into it when needed.
Demand Response Management: Cellular networks support demand response management systems, which adjust demand for power in real-time, based on supply conditions.
Overall, cellular networks, with their evolving capabilities from 4G LTE to 5G, offer flexible, scalable, and high-speed communication solutions that can support a wide range of applications in grid modernization. They are especially useful for applications that require wide coverage and mobility.
RF Mesh networks play a significant role in grid modernization and OT 2.0, providing robust and reliable communication systems that are essential to the operation of a modern, "smart" grid. Here's an overview of their usage:
Smart Metering: Mesh Networks support the communication of data from a large number of meters to the utility, enabling near real-time monitoring of power usage.
Distribution Automation: These networks also support the automation of distribution systems, enabling real-time monitoring and control of grid components, helping help to quickly identify and address issues, reducing the duration and impact of outages.
Integration of Distributed Energy Resources (DERs): As with Cellular, RF mesh networks can also support the integration of DERs into the grid.
Demand Response: Demand response programs are also supported by RF Mesh networks, allowing utilities to manage power load based on real-time supply and demand conditions.
Satellite and microwave communication networks, while typically more expensive and having higher latency than terrestrial alternatives, offer unique advantages that can make them a valuable component of OT 2.0 efforts. They are often used for point-to-point communication, and are a popular choice for connecting remote sites or establishing a communication link where it's not feasible or cost-effective to lay cables.
These networks provide high-capacity, reliable, and secure communication links, making them well-suited to a variety of applications in OT 2.0, including:
Remote Area Connectivity: One of the primary uses of satellite and microwave networks is to provide connectivity in remote or hard-to-reach areas where other types of networks may not be feasible or cost-effective. This includes rural areas, mountainous regions, islands, and other geographically challenging locations.
Backup Communication System: Satellite and microwave networks also serve as a backup communication system for critical grid operations. This can be especially important in emergency situations, such as natural disasters, when terrestrial communication networks may be damaged or overloaded.
Distribution Automation: This can include everything from remote monitoring of equipment health to real-time control of circuit breakers or other devices to manage power flows.
Integration of Distributed Energy Resources (DERs): Satellite and microwave networks can also support the integration of DERs, especially those located in remote areas.
An interesting aspect of networks for utility use in OT 2.0 is that the lifecycle for technologies within a utility are often very long (15-20 years). This does not correlate well with the rapidly changing landscape of network infrastructure, where technologies often change every 5-7 years. This was clearly witnessed in the issues with AMI 1.0 2G and 3G meters that were necessarily exchanged or provided with an upgraded network card, when the major carriers deprecated those networks. With the vast number of connected devices in an OT 2.0 system, it is critical that OT 2.0 strategies consider this network impact and select networks which may be better suited to provide the necessary operational longevity.
