Cellular IoT- and Bluetooth LE-powered device enables remote monitoring of smart power grids


RAM-1 employs Nordic’s nRF9160 SiP and nRF52811 SoC to allow grid operators to immediately take corrective action in the event of a network fault

Nordic Semiconductor today announces that Maribor, Slovenia-based innovation lab, IRNAS, has selected Nordic’s nRF9160 low power SiP with integrated LTE-M/NB-IoT modem and GPS in combination with the nRF52811 Bluetooth® Low Energy (Bluetooth LE) multiprotocol System-on-Chip (SoC) to provide the wireless connectivity for ‘RAM-1’. The product enables the remote monitoring of power grids and surge arresters. Surge arresters protect electrical equipment from atmospheric and switching overvoltages. IRNAS developed the device for Izoelektro, a Slovenian firm supplying utilities and energy companies with solutions that help set up, maintain, and restore electrical energy systems.

Once deployed on transmission towers throughout an electricity network, the RAM-1 device can be easily commissioned via a smartphone app using Bluetooth LE wireless connectivity provided by the nRF52811 SoC. In addition to commissioning the RAM-1 device, the Nordic-powered Bluetooth LE connectivity also provides a method of collecting data in remote locations where there is no LPWAN coverage, as well as providing a back-up channel for upgrading the device and applying different network settings if necessary. 

Multimode LTE-M/NB-IoT connectivity

Once installed, RAM-1’s integrated voltage, temperature, accelerometer, and surge counter sensors enable the user to remotely monitor, analyze, and report a range of potential faults, for example, excessive temperature as a result of a possible fire, the collapse of a transmission tower, power outage, or power surges. Enabled by the nRF9160’s SiP’s multimode LTE-M/NB-IoT connectivity and GPS trilateration, the device periodically relays the data—and the precise location of the monitored device—to the proprietary ‘RAM-CENTER’ web platform, allowing grid operators to immediately take corrective action in the event of a fault, and helping improve the reliability and stability of the overall network.

nRF Connect SDK’s support for the Zephyr RTOS ecosystem hugely streamlined the development process
Luka Mustafa, IRNAS

To avoid the need for regular maintenance or replacement, the ruggedized RAM-1 is powered by a primary Li-Mn02 cell and is designed to last up to 20 years in the field. This extended battery life is achieved thanks in part to the low power capabilities of Nordic’s nRF9160 SiP. The nRF9160 is optimized for low power operation, supporting PSM and eDRX power saving modes, that in combination with the device’s networking logic keeps power consumption below 10µA in sleep mode.

The nRF9160 SiP is certified for global cellular IoT applications and comprises a dedicated application processor and memory, multimode LTE-M/NB-IoT modem with integrated RF front end (RFFE), GPS, and power management in a compact 10 by 16 by 1mm package. The 64MHz Arm® Cortex®-M33 processor includes 1MB Flash and 256kB RAM, a range of analog and digital peripherals, automated power and clock management, Arm TrustZone® for trusted execution, and Arm CryptoCell™ 310 for application layer security. The processor communicates with the LTE modem through a BSD secure sockets API and supports the application layer protocol (for example CoAP, MQTT or LWM2M) and the application itself. 

The nRF9160 SiP’s LTE modem supports both SIM and eSIM, offers 700 to 2200MHz LTE band support, 23dBm output power, and single pin 50 Ω antenna- and UICC-interfaces. The LTE stack layers L1-L3, IPv4/IPv6, TCP/UDP, TLS/DTLS are part of the modem firmware. Related products include the nRF9160 DK, a precertified single board development kit and the nRF Connect SDK, a software development kit which includes application layer protocols, application examples, and LTE modem firmware offered as precertified and precompiled downloads.

Nordic’s nRF52811 multiprotocol SoC is a fully-featured connectivity solution combining a 64MHz, 32-bit Arm® Cortex® M4 processor, with a 2.4GHz multiprotocol radio (supporting Direction Finding, Bluetooth 5.2, Thread, Zigbee, IEEE 802.15.4, and proprietary 2.4GHz RF protocol software) featuring 4 dBm output power with -97 dBm sensitivity (at 1 Mbps in Bluetooth 5 mode), and 192 kB Flash memory plus 24 kB RAM. 

The nRF52811 SoC is supplied with Nordic’s S112 SoftDevice, a Bluetooth 5-certified RF software protocol stack for building advanced Bluetooth LE applications. The S112 SoftDevice features Central, Peripheral, Broadcaster and Observer Bluetooth LE roles, supports up to four connections, and enables concurrent role operation.

Zephyr RTOS support

“The nRF9160 was selected based on a detailed evaluation of its radio performance and firmware toolset, but the key factor was the nRF Connect SDK’s support for the Zephyr RTOS ecosystem that hugely streamlined the development process,” says Luka Mustafa, CEO, IRNAS. “This helped resolve a large number of friction points in creating a robust end-to-end solution, allowing more development resources to be allocated to the core product.”

“From a device that originally reported the state of surge arresters, RAM-1 has rapidly become a IoT device for remote monitoring, machine learning, and advanced analytics of power grids,” says Jure Pungerčar, Deputy CEO, Izoelektro. “We are excited about the possibilities of a truly smart power grid and the ability to improve the operation, stability, and reliability of electricity distribution.”