Case Study
By John Coates, ElectriCities
ElectriCities, a public power membership organization, provides management services to North Carolina’s municipal power agencies and serves 90 member municipalities and 1.2 million customers throughout North Carolina, South Carolina and Virginia. The organization provides technical assistance, customer service, safety training, emergency assistance, government affairs and legal assistance to its customers.
In providing these services to municipally-owned electric utilities, ElectriCities relies on local telemetry networks. Telemetry is not only an integral part of billing-allowing utilities to produce more accurate billing, especially during peak usage periods-it also provides data on power capacity and consumption, which gives ElectriCities insight into the energy reserves that should be scheduled for peak load or off-peak periods. In addition, telemetry networks serve as the foundation for another layer of digital intelligence when it comes to analyzing power consumption. Telemetry networks are essentially the “eyes and ears” of ElectriCities SCADA systems, helping to optimize grid performance and sell unused power.
When the ElectriCities legacy telemetry polling solution became too costly to maintain and was also vulnerable to weather-related disruptions, the organization searched for a more reliable, secure, cost-effective and weather-resistant telemetry solution that also would be easy to implement, manage and control.
The result of this search yielded a network with the type of smart grid functionality that allows ElectriCities to more efficiently monitor and control the two-way flow of energy across operations. In addition, the organization realized significant savings annually on telemetry charges by selecting a commercial 4G LTE Cat m1 network and implementing intelligent 4G LTE routers to obtain real-time data on substation meters and generators in the field.
Situational Analysis
ElectriCities maintains a complex network covering thousands of square miles, collecting data from a variety of meters, generators and telemetry equipment to offer comprehensive communications and management services to its member utilities. The traditional method of installing copper 56k circuits to each site was cost-prohibitive and highly vulnerable to possible lightning strike damage. An alternative communications method, such as fiber optics, could reduce the threat of lightning strikes but also was prohibitively expensive and excessive for the relatively limited bandwidth needs of each site.
Ultimately, the solution had to be able to manage a varied mix of meters and generators in the field, and provide robust meter polling data communication capabilities to replace a legacy system that relied on copper 56k circuits at each site. Given the need for a cost-effective, weather-resistant telemetry solution that would be easy to implement and manage, ElectriCities chose to leverage public cellular communications for real-time monitoring and control of existing telemetry networks.
Solution
Wireless telecommunications providers have optimized 4G LTE networks to meet the growing requirements of Internet of Things (IoT) applications. These networks offer increased traffic-carrying capacity, network efficiency and scalability, and deliver low latency and improved building penetration. This means they are well suited for many types of IoT applications requiring speed and responsiveness.
Telecom providers continue to innovate when it comes to leveraging cellular networks for IoT applications. In March 2017, Verizon announced the launch of the first nationwide commercial 4G LTE Cat m1 network. Cat m1 LTE is distinct from the LTE networks used by smartphones because it can also host high-speed IoT applications. In LTE Cat m1 networks, uplink and downlink speeds are capped to minimize the cost of connectivity for devices that do not need constant communication with the network.
Once ElectriCities decided on 4G LTE as the network infrastructure, the focus turned to connectivity hardware optimized for cellular networks. The ability to quickly bring hardware online was key, as was the requirement that the hardware, in this case cellular routers, was secure, had the flexibility to run on multiple carriers, and could be managed via a centralized management tool.
ElectriCities selected the Digi TransPort® WR31 LTE router from Digi International because it provided the right combination of reliability, security, control and flexibility. The router is subjected to VPN performance and HALT testing, and features software-defined multicarrier support that permits the same router to switch between AT&T, Verizon and all other North American LTE carriers.
There are some additional key features of the router that made it a desirable choice for ElectriCities. It employs mechanisms to monitor the health of the connection through active (e.g., pings) or passive techniques (via stateful firewall), then takes corrective action via connection resets and reboots to help maintain connection persistency. This allows for a consistent connection during the periods when cellular networks go through maintenance and upgrades and check for inactive devices, either of which can result in a device losing its connection to the network. The router also includes a comprehensive analyzer that allows traffic on virtually any interface or protocol within the router to be inspected. This can be an invaluable tool when determining traffic flow and ensuring secure passage of data from one point to another.
In addition, Digi routers include stateful firewalls. This enterprise-level firewall provides customizable security and routing functionality. In addition, the routers support multiple types of VPN connections and encryption methods, and all external services and ports can be disabled on the routers to ensure physical security of the devices. ElectriCities’ new routers maintain a more reliable VPN connection than the cellular modems it used in the past.
ElectriCities’ new telemetry solution has allowed it to improve and enhance power delivery to member municipalities and customers. It is now able to more reliably and efficiently supply management and communications services across a vast geographic area.
In providing services to municipally-owned electric utilities, ElectriCities relies on local telemetry networks.
John Coates is a senior EMS application engineer for ElectriCities.
