H2scan Sentinel PRO Transformer IoT and Power Quality Monitor

Transformer health and power quality in one connected unit

Sentinel PRO is an H2scan grid-intelligence IoT monitor that combines transformer health monitoring with advanced power-quality measurement. Paired with GRIDSCAN 5000 or 6200 hydrogen sensors and the H2cloud platform, it gives utilities fleet-wide visibility of hydrogen, voltage, current, harmonics and other conditions that can contribute to transformer failure.

The unit includes a low-cost IoT modem that supplies regulated power to the GRIDSCAN sensor and sends dissolved-gas and oil temperature data to H2cloud for alerting, trending and analysis. Communications cover global cellular (3G, 4G, LTE, NB-IoT), optional Modbus/TCP and a Last Gasp alert on interruption, with 60+ days of internal secure data storage.

Technical specifications

Applications and installation notes

The datasheet frames the unit for distribution transformers on utility networks where variable generation, such as solar, and other disturbances stress equipment. Measured power-quality data helps to find the root cause of a disturbance, and the hydrogen link shows whether the transformer itself is deteriorating. Oman and GCC distribution utilities with growing solar penetration face exactly this question (our application note).

Current is measured non-intrusively with Rogowski coils in four ranges up to 6000 A, so no outage is needed to fit the clamps. Voltage connects via a fused insulation piercing clamp on poles or a fused carrier at ground-mount units. See related power products under power meters and power quality.

Power-quality capabilities in detail

Voltage measurements listed include frequency averaged over 10 seconds, flicker (Pst and Pit), supply voltage dips and swells, voltage interruption, supply voltage unbalance, voltage harmonics to the 50th order, inter-harmonics, rapid voltage change, phase angle and RMS values per one cycle and per 10/12 cycle. Current measurements add neutral current, harmonics to the 40th order, unbalance, phase angle and RMS values.

Calculated metrics include active and reactive power, total harmonic distortion, dips, brown-outs and excursions. Event thresholds are given as supply interruption below 80%, low voltage below 94%, high voltage above 110%, undercurrent below 1% of rated current and overcurrent above 100% of rated current. High-speed sampling covers 480 V and below, three-phase voltage and current via Rogowski coils.

Because Sentinel PRO carries a 1000 V CAT III and 600 V CAT IV safety category, it can be connected at the low-voltage side of distribution transformers; always follow the utility connection procedure and the manufacturer manual for the voltage taps and clamps.

Because the same enclosure carries the cellular modem, the power-quality analyzer and the sensor supply, one installation visit can place both transformer and grid monitoring at a distribution substation. Data log storage of more than 60 days protects records during communication outages, and the Last Gasp alert reports a supply interruption at the moment it happens.

Document control: the technical data sheet used here is H2scan document 90000237, revision R3, with an 8.20 mark in its footer. H2scan publishes a quick start guide for Sentinel PRO separately, and we suggest requesting it, together with details of the cellular plan and the H2cloud account, before planning a rollout.

Planning a Sentinel PRO deployment

Sentinel PRO is most useful where a transformer has no existing SCADA link, such as distribution transformers, remote substations and transformers feeding oil and gas field facilities. General engineering note (not from the datasheet): before ordering, check cellular coverage at each site, decide whether data will go only to H2cloud or also to the utility SCADA over Modbus/TCP, and agree with the IT and security teams how cloud data will be accessed. The 60-day internal storage covers communication outages, and the Last Gasp alert reports a supply interruption.

The nominal 240 VAC 50 Hz supply suits the low-voltage systems used in Oman and much of the GCC, and the 0 to 400 VAC measurement range covers phase-to-neutral and many phase-to-phase measurements on low-voltage networks; check the connection diagram for the exact arrangement. Combining power quality data, such as harmonics and voltage events, with GRIDSCAN hydrogen readings helps link a rise in hydrogen to loading or supply conditions, which is valuable when deciding whether a transformer needs inspection or only a change in operation.

Related H2scan products: H2scan GRIDSCAN 5000 Transformer Dissolved Hydrogen Monitor, H2scan GRIDSCAN 6200 Multi-Sense Transformer Health Monitor, H2scan HY-ALERTA 2620 Explosion Proof Hydrogen Monitor, H2scan HY-ALERTA 5020 Self-Calibrating Hydrogen Monitor, H2scan HY-OPTIMA 2700 Explosion Proof In-Line Hydrogen Analyzer and H2scan HY-OPTIMA 5232 Self-Calibrating Hydrogen Process Analyzer.

Documents and quotation

The H2scan Sentinel PRO technical data sheet is attached. Seven Star LLC is an independent supplier in Muscat; send the transformer type, voltage level and connectivity requirements to request a quotation.