Utility companies are in the process of incorporating greater amounts of real-time monitoring and control into the electric grid. This data collection and control is no longer limited to the transmission grid, but is being driven deep into the distribution grid and beyond (more on that later). These intelligent devices and sensors that are being deployed require secure and reliable data connectivity to be of effective use to utilities.
Wireless technologies are the dominant method today to obtain the data, and new wireless standards have been created to help utilities scale these networks. One specific standard, IEEE 802.16s, is at the forefront given its ability to effectively leverage narrowband VHF and UHF licensed frequencies.
For many years, utilities have managed to keep their SCADA systems secure and functional using their own, privately owned telecommunications networks. However, new sensor, processing and data storage capabilities are placing increased data demands on these networks and creating a strain within the existing telecommunications systems. This rapid increase of intelligence and distributed energy resources (DER) has left mission critical industries to identify secure, reliable and scalable network options, capable of handling increased data throughputs for existing and future needs.
Part of their challenge is to obtain enough radio frequencies to modernize these networks. In the United States, as opposed to many other countries around the world, the Federal Communications Commission (FCC) has not allocated dedicated, nationwide licensed spectrum specifically for modernizing the power grid. This is why groups like the Utilities Technology Council (UTC), Electric Power Research Institute (EPRI), and industry leaders have thrown their support behind new wireless standards, like IEEE 802.16s that make more effective use of legacy frequency bands for modernized intelligent grid networks.
Creating Grid Intelligence
New devices are being proposed at a rapid rate to provide greater control and real-time visibility to both the transmission and distribution grids. On the distribution side, this list of technologies includes capacitor bank controllers, voltage regulators, reclosers and distributed energy resources control units (e.g. rooftop solar inverters). Furthermore, sophisticated technologies such as Phase Measuring Units have been proposed for the distribution grid in order to increase grid stability. There are many times more devices and data points on the distribution electric grid than have been on the transmission grid, where SCADA has historically existed, and there are exponentially more data points from PMUs than historical SCADA systems. Many utility communications networks were originally designed for basic SCADA of the transmission grid, which had many fewer data points. The communications networks supporting these legacy networks are no longer capable of handling the increased data needs.
The introduction of intelligence has also created a new demand for the cyber and physical security of the network itself and all of the mission-critical devices connected to it. Hundreds of thousands of sensors and controls, without proper encryption or connectivity, can create multiple vulnerabilities for malicious cyber activity. Denial of Service attacks targeted towards U.S. utility operations has further highlighted the concerns surrounding modernization and the use of commercial or unlicensed wireless networks. These attacks have only served to promote the need to use private licensed wireless networks that are separated from commercial wireless networks.
Until recently, there were only a few different options for launching intelligent grid networks:
- The use of standard-based unlicensed networks like WiFi which have increased security vulnerabilities and coverage limitations
- The use of proprietary technologies in licensed frequencies which lack a sufficient ecosystem for longevity
- Reliance on commercial networks with security and reliability concerns. These deficiencies led to the drive for a new standard that would leverage available licensed frequencies with greater capacity.
The Need for Standards
Standard technologies are becoming vital to utilities that seek a multi-vendor ecosystem of private licensed network solutions capable of operating in existing licensed spectrum. Many of the legacy narrowband technologies are based on proprietary single-vendor technologies. Relying on these companies creates much greater risk for the utility in terms of future obsolescence. Most utilities do not typically have access to enough radio frequency (RF) spectrum to deploy standards-based consumer technologies like LTE. Nor does LTE enable the quality of service or security elements required by utilities.
In October 2017, IEEE ratified and published a new wireless standard known as IEEE 802.16s. The standard leverages existing licensed frequencies that are readily available to utilities. This includes frequencies located in the legacy paging channels, AMTS and IVDS spectrum at 200 MHz, the Upper 700 MHz A Block, the NPCS band at 900 MHz and now at 1.4 GHz. The standard allows for higher throughput, including multi-megabit data rates, and greater quality of service as compared to legacy narrowband technologies. The protocol supports very long transmission ranges (up to 30 miles from a base station) which serves to minimize the amount of infrastructure. Lastly, it uses Time Division Duplexing which is a highly efficient protocol for asymmetric data networks as found in the electric grid.
As more intelligence and data is incorporated into the power grid, utilities will require network upgrades that enhance security, reliability and availability. With this narrower channel standard and new technologies, utilities are able to more effectively monitor and control mission-critical applications within the grid on private, licensed, secure wireless communications networks.
