Battery Energy Storage Systems (BESS) Monitoring

Reading Your BMS, Inverters and Site Plant

Most BESS plant sstems already know when something is wrong. Battery management systems, inverters (PCS), HVAC units and auxiliary UPS systems usually have a Modbus/TCP or SNMP interface that provides live readings and alarm conditions.

Our monitoring base units connect to this equipment over the site network and use virtual sensors to read them, so several containers, inverters and cooling units can be monitored from a single base uit system. Typical readings include cell voltages and temperatures, state of charge, insulation faults, inverter output and trip alarms, HVAC supply and return temperatures, and UPS runtime. We can display this information on a dashboard and send automated alerts for change-of-state conditions, or when readings move outside preset thresholds. For equipment without a Modbus or SNMP card, such as fire panels, transformer temperature relays and grid protection relays, volt-free (dry) contacts provide a simple way to pick up alarms, faults and isolations.

Early Warning of Thermal Runaway and Fire

The biggest risk on a battery storage site is thermal runaway, where a failing lithium-ion cell overheats and can spread to the cells around it. A failing cell usually gives off hydrogen and carbon monoxide before any smoke or visible fire, so off-gas detection in each container gives the earliest possible warning. Alongside gas detection, we monitor smoke detectors, container temperatures at several heights, and the status outputs from the fire panel. That means you know straight away if suppression has discharged, developed a fault or been left isolated after maintenance. Alerts go to your engineers, your control room and, where required, the people who need to brief the fire service, so responders know which container is affected before they arrive.

Unmanned and Remote BESS Sites Over 4G/5G

Most battery storage sites are unmanned, and many are remote. They cannot always rely on a fixed network connection, and the SCADA link itself may be what fails. Our monitoring base units are available with a built-in 4G/5G modem, or can connect to a compatible external modem, giving an independent route for alerts. We recommend clients supply their own network-agnostic SIM cards, but we can programme and set these up as part of our system configuration service. The modem can be used for:

• SMS text messages with live data
• Email alerts with specific live readings
• Spoken voice-call alerts, on a voice-enabled modem version
• Scheduled heartbeat messages, so silence from a site is itself a warning
• An OpenVPN connection back to a central monitoring platform for remote diagnostics and maintenance

There are some practical points for modem use. Modems are normally factory fitted, though some devices can use an external modem. Mobile signal quality depends on the site and its location, and may need careful aerial positioning, normally within 3m of the base unit. Steel battery containers and enclosures block mobile signals, so aerials are usually mounted outside, on the control building or container roof.

Physical Sensors for BESS Sites

Physical sensors add an independent layer of monitoring alongside the BMS.

• Off-gas detectors for hydrogen and carbon monoxide, connected by volt-free contacts or 4-20 mA outputs
• Smoke detectors and fire panel status contacts
• Calibrated temperature and humidity sensors
• Spot water sensors and water leakage detection ropes
• AC voltage sensors for grid and auxiliary supplies
• Isolated DC voltage sensors
• Airflow sensors for HVAC units and ventilation
• Security door contact sensors for containers, inverters and buildings
• PIR motion detectors and sirens and strobes for perimeter security

BESS Monitoring and Maintenance Contracts

As well as supplying and installing monitoring systems, we can provide remote monitoring as part of a maintenance contract, with 24/7 monitoring and remote diagnostics for your battery storage sites. Please contact our Projects Team to discuss how we can monitor your BESS sites and improve their safety, availability and performance.

Please contact our Projects Team to discuss how we can monitor your BESS system and improve the overall reliability and operational performance.