(Note: Amit Kumbasi co-authored this blog)
With recent advancements in technology and the move toward a digital grid, wireless connectivity is gaining more traction as an extension to wired connectivity for grid equipment such as circuit breakers, merging units, photovoltaic inverters, electric vehicle chargers and other asset monitoring systems. Wireless connectivity is a cost attractive solution for distributed energy resource management and grid asset health monitoring given its reduced deployment time for grid protection and control.
Wireless technologies, such as Wi-Fi, Sub-1 GHz, Bluetooth® low energy and multiband standards, can stream large amounts of data at manageable power levels. Users can seamlessly monitor, protect and control grid equipment locally or remotely by accessing the system data through the asset or the cloud without compromising grid security. Wireless asset monitoring can be easily retrofitted onto existing equipment without adding the complexity that comes from underground cabling.
Let’s discuss five key considerations when integrating Wi-Fi onto grid equipment.
Consideration No. 1: choosing an architecture for Wi-FiChoosing the appropriate network architecture depends on the network coverage type and the location of the assets, data storage and the end users. You have two architectures from which to choose:
Figure 1: Cloud connection through external AP
Figure 2: Networking of equipment through a SimpleLink AP
Consideration No. 2: provisioningProvisioning is a process of providing the network credentials of a device to connect to a wireless network for the first time. The CC3220, CC3235 provides two secure methods of provisioning:
Consideration No. 3: data transferOne of the key benefits of Wi-Fi connectivity is on-demand access to large streams of grid data. The data could include parameters such as phase voltage, current, power, etc., and factors such as operating temperature, vibration and insulation breakdown, which indicate the health of the asset. The data could also be used to monitor system/equipment status.
For other applications, wireless access enables the control of equipment settings by sending commands through the cloud to remote grid assets. It is also possible to update equipment firmware through the cloud using over-the-air updates.
Consideration No. 4: power consumptionWhile access to the power supply is not a concern, minimizing current consumption of a wireless subsystem is important as most grid assets operate over decades. The average power consumption for Wi-Fi technology depends on factors including data size, interval and latency. Based on the data transfer interval and latency, there are two modes of operation to select:
Table 1: CC3220 Wi-Fi power consumption chart
Figure 3 shows the switchable power profiles.
Figure 3: Wi-Fi switchable power profiles
Consideration No. 5: secure remote monitoring and network securitySecurity is primary importance in grid to help mitigate the threat from unauthorized users getting access to sensitive data and control of the grid equipment. One of the exposure points for the threat is in the network layer where the grid assets connect to the cloud. Our SimpleLink Wi-Fi device enables networking security, local area network (LAN) security and physical device-level security at different levels of connectivity. More details on the security features of the device can be found in this application report.
TI’s next generation SimpleLink Wi-Fi deviceThe CC3235S, CC3235SF SimpleLink Wi-Fi device supports 5 GHz in addition to 2.4 GHz and has Bluetooth® Low Energy/2.4-GHz coexistence. And while security is one of the biggest challenges of wireless communication, advancements such as hardware crypto accelerators, file encryption, file authentication, clone protection and secured boot have been incorporated into the CC3235S, CC3235SF to help prevent unauthorized users from gaining access and control. These devices provide enhanced security with Federal Information Processing Standard (FIPS) 140-2 Level 1 certification, with up to 16 concurrent secure sockets. Figure 4 shows the functional block diagram for the CC3235S, CC3235SF.
Figure 4: Functional CC3235S, CC3235SF block diagram
ConclusionGrid engineers can use Wi-Fi connectivity as an extension or as a redundant communication path in addition to wired communication. Wi-Fi can be used to enhance connectivity in order to monitor and control any asset from a remote location through the cloud. Our CC3220S, CC3220SF and CC3235S, CC3235SF Wi-Fi radios with an integrated network processor and applications processor (ARM® Cortex®-M4), extensive security features and our reference designs, provide an easy, quick and secure way to add Wi-Fi connectivity to residential or substation grid equipment.
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