Why Utility Communications Cannot Fail

The utility sector operates under a constraint that very few industries share: the cost of a communications outage is not measured in inconvenience or lost revenue alone. When a secondary substation goes dark on the SCADA network, protection relays become unmonitored. When a battery energy storage system loses its control comms, grid operators lose the ability to dispatch, curtail, or protect the asset. When a wind farm collection network drops off a telemetry platform, the maintenance team is flying blind on turbine faults.

Regulators in the UK measure interruption minutes. Ofgem tracks customer interruptions and customer minutes lost as primary distribution network operator performance metrics. Every minute a fault is undetected because the comms network was down is a minute that counts against those figures. That context explains why utility procurement teams specify industrial-grade networking hardware and reject consumer or light-commercial equipment, regardless of price advantage. The tolerance for failure is effectively zero.

The same logic applies to cybersecurity. UK utility operators are in scope for the NIS (Network and Information Systems) Regulations and the NCSC Cyber Assessment Framework. BESS assets that can export to the grid are subject to the ENA’s Engineering Recommendations. These frameworks impose concrete technical requirements – network segmentation, encrypted communications, patch management, incident logging – that network hardware must support. Again, consumer-grade equipment does not make the cut.

Cellular Connectivity for Secondary Substations and Grid-Edge Sites

The most cost-effective and rapidly deployable comms path for secondary substations, remote switching stations, and grid-edge BESS sites in the UK is cellular. Installing new fibre to a rural distribution substation can cost tens of thousands of pounds and take months to provision. A well-specified cellular router with dual SIM – on verified, independently tested mobile network operators – gets a site connected within hours and delivers a level of WAN redundancy that a single fibre connection structurally cannot match.

The key requirement at these sites is not raw bandwidth. DNP3 SCADA traffic over TCP, IEC 60870-5-104, and Modbus TCP are all modest in terms of data volume. What matters is tunnel stability, consistent low latency, and – critically – the behaviour of the failover mechanism when the primary WAN path goes down.

For guidance on SIM selection, MNO verification, and multi-SIM strategy for utility deployments, see the industrial SIM cards section and the guide to multi-network SIM options for IoT and M2M.

Data Communications for Renewable Power Generation

Wind and solar sites present a networking challenge that is distinct from substation connectivity. Individual generation assets – turbines, inverter strings, power conversion systems, tracker controllers – are distributed across a site that may cover several square kilometres. Each needs to report generation data, fault codes, and control status back to a site-level SCADA or SCADA-equivalent platform. That platform then needs a reliable WAN path to the grid operator, the asset manager, or both.

The site collection network is typically a combination of wired Ethernet for fixed equipment – switchrooms, inverter skids, battery blocks – and some form of wireless connectivity for distributed assets where cable runs are impractical. Ring topologies are common in wind farm electrical design, and the data network often mirrors the ring architecture to provide resilience against a single cable fault isolating a section of the site.

Compact Cellular for Remote Generation Assets

Distributed Sensor Monitoring with LoRaWAN

Beyond the SCADA and control layer, there is a growing requirement on renewable sites for dense environmental and condition monitoring – soil temperature and moisture sensors for ground-mounted solar, vibration monitors on turbine main bearings, equipment temperature logging on battery modules. Deploying Ethernet or cellular to each individual sensor point is impractical at scale. This is the problem LoRaWAN was designed to solve.

LoRaWAN operates on sub-GHz licence-exempt spectrum. A single gateway with a modest antenna installation can cover several kilometres of open ground, collecting data from hundreds of battery-powered sensors. The sensors themselves can run for years on coin cells or small solar cells. The data rates are low – suitable for periodic readings and alerts, not video or high-frequency waveform capture – but that is exactly what environmental monitoring requires.

For a full overview of how LoRaWAN fits within a utility IoT architecture, including frequency planning and network server options, see the LoRaWAN technology guide.

The Management Layer: Milesight DeviceHub and Development Platform

Industrial hardware resilience solves the physical connectivity problem. Operating a distributed fleet of that hardware at scale – across dozens of substations, BESS sites, and generation assets – requires a management and integration layer that most utilities do not want to build themselves. This is where Milesight’s platform capabilities become as important as the hardware specification.

The two relevant components are DeviceHub – Milesight’s cloud-based device management platform – and the Milesight Development Platform, a low-code integration and application environment that allows operators to build monitoring dashboards, alert workflows, and data pipelines without writing infrastructure code from scratch.

DeviceHub provides centralised visibility and control of the full Milesight router and gateway estate. Key capabilities for utility fleet management include:

• Real-time device status across the full fleet – online, offline, signal strength, active WAN path, VPN tunnel state
• Remote configuration push – update firewall rules, VPN parameters, or APN settings across hundreds of devices without site visits
• Over-the-air firmware management with scheduled update windows and rollback capability
• Alert rules for connectivity loss, signal degradation below threshold, device reboot events, and WAN path changes
• Configuration templates for consistent and auditable provisioning of new sites – relevant to EPC contractors deploying BESS or solar sites at volume
• Audit log of all configuration changes – supports NIS compliance evidence requirements

For a detailed look at the Milesight Development Platform and how it can be used to build custom monitoring and integration applications on top of the hardware estate, see the full post: Milesight Development Platform – Building IoT Applications Without Starting From Scratch.

Cybersecurity – Built In, Not Bolted On

The NIS Regulations require operators of essential services – which includes electricity distribution and large-scale generation – to implement appropriate and proportionate technical and organisational measures to manage risks to network and information systems. The NCSC’s Cyber Assessment Framework translates this into four objectives: managing security risk, protecting against cyber attack, detecting cyber security events, and minimising the impact of incidents. These are not aspirational standards. They are the framework against which Ofgem and the relevant competent authorities will assess compliance.

Milesight industrial routers ship with the features this framework demands as standard capability, not optional add-ons requiring additional licensing.

For a broader discussion of cellular security considerations in industrial and utility deployments, including SIM-level security and private APN options, see the security section and the guide to private APN for isolated IoT connectivity.

A Reference Architecture for BESS and Secondary Substation Sites

Pulling the hardware and platform elements together, a complete Milesight-based communications architecture for a utility-scale BESS site or secondary substation would typically be structured as follows.

This architecture supports the communications requirements of the ENA Engineering Recommendation for controllable BESS assets (ER G99 and the associated Tactical Solution framework) and provides the evidential basis for CSRB registration and NIS competent authority review. It can be deployed by a competent systems integrator within a single site visit for initial commissioning, with all subsequent management handled remotely.

Choosing the Right Milesight Router for Your Application

The UR-series covers a broad range of deployment scenarios. A quick selection guide for utility applications:

• UR32: Space-constrained cabinets, turbine base enclosures, solar monitoring kiosks – where physical footprint is the primary constraint and 4G LTE dual-SIM suffices
• UR35: Standard secondary substation, BESS site, or remote switching station deployment – the most widely deployed model in utility applications, balancing interface density with compact form factor
• UR75: Primary substation backhaul, high-availability aggregation points, hybrid fibre-cellular topologies, or sites requiring 5G capability for future-proofing
• UG65/UG67: Site-level LoRaWAN gateway for environmental monitoring, access monitoring, and condition-based maintenance sensor networks

Full specifications, ordering codes, and antenna options for all Milesight router models are covered in the Milesight industrial routers section. Antenna selection guidance for utility cabinet and outdoor pole mounting is in the antenna and RF guide.