Dissolved hydrogen in transformer oil, measured continuously and maintenance-free
The GRIDSCAN5000 continuously measures the hydrogen dissolved in transformer oil, the first gas to appear when an internal fault begins. It screws directly onto a tank valve, has no moving parts and runs unattended for its whole service life.
Advantages
It warns before any other signal
Hydrogen is the first gas generated by an incipient arc, a partial discharge or a hot spot. Watching it rise in real time leaves room to schedule the intervention instead of discovering the problem in the six-monthly oil analysis.
No calibration, no consumables
The sensing element is solid state and calibrates itself: no membranes, no calibration gases, no pumps and no chromatography columns, and nothing to replace between transformer inspections.
Affordable fleet-wide
Its price and its simple installation make it viable to equip not only the critical assets but the whole fleet, which is where continuous monitoring really pays.
Built for outdoor service
IP68 ingress protection — 7.62 m of water for 14 days —, C5M corrosion class equivalent to a marine environment and operation from −40 to 70 °C, with vibration testing and a 30 g shock rating to IEC 60068.
Immediate integration
It communicates over Modbus RTU or DNP3 on two-wire RS-485, both stand-alone and inside third-party multi-gas monitors, and supports a 4-20 mA output through the matching module.
Applications
- Power and distribution transformers, new or in service.
- Wind and solar farm transformers, with high harmonic content.
- Network transformers installed in underground vaults.
- Offshore platforms and substations in salt-laden air.
- Railway traction and industrial transformers.
About the product
The oil-calibrated version mounts horizontally with the air-bleed assembly; the gas-calibrated version accepts horizontal or vertical mounting in the head space. Both need a 3/4" ball or gate valve (≥ DN20) and thread sealant, with no galvanised fittings.
A single shielded four-conductor 18 AWG cable, with a female M12 connector and IP67/IP68 rating, carries power and communications to the control cabinet over typical runs of 5 to 30 m; from there, the RS-485 bus reaches up to 1,000 m. The sensor itself keeps one year of history, so a communications outage leaves no gap in the data.
The Windows configuration utility connects over RS-485 or through an Ethernet-to-RS485 bridge and gathers the whole commissioning process into four tabs: real-time data with capture to CSV, protocol and address, clock synchronisation, owner, substation and transformer identification, and selection of the insulating liquid — mineral, silicone, natural ester or synthetic ester with its own Ostwald slope and offset.
The range is completed by the high-performance version, accurate to ±10 % or ±15 ppm, the continuously self-calibrating version, which calibrates without interrupting the measurement, and an extended-range version from 250 to 50,000 ppm for nitrogen blankets with high concentrations.
Technical specifications
| Measuring range | 25 to 5,000 ppm in oil; 25 to 5,000 ppm in-oil equivalent on the gas-phase version |
| Accuracy | ±20 % of reading or ±25 ppm (±10 % or ±15 ppm on the high-performance version) |
| Repeatability | ±10 % of reading or ±15 ppm, whichever is greater |
| Response time | Under 60 minutes |
| Cross-sensitivity | Below 2 % to H2O, CO2, C2H2, C2H4 and CO |
| Data logging | 1 year of history held in the unit |
| Insulating liquids | Mineral oil, silicone, natural ester and synthetic ester |
| Temperatures | Ambient −40 to 70 °C; oil −40 to 105 °C; gas phase −40 to 80 °C |
| Communications | Two-wire RS-485, Modbus RTU and DNP3; 19,200 baud, 8N1 as shipped |
| Power supply | 12 to 48 VDC; 10 W maximum consumption |
| Connection | 3/4"-14 NPT thread; 4-wire M12 electrical connector |
| Dimensions | 151 × 39.6 × 39.6 mm |
| Ingress protection | IP68 to IEC 60529; C5M marine corrosion class |
| Certifications | CE marking, FM 6520:2022 in liquid phase, RoHS 2011/65/EU, IEC 61010-1 and IEC 61326 |
| Warranty | 3 years on the unit and 10 years on the hydrogen sensing element |
Frequently asked questions
Does it need periodic calibration?
No. The sensor self-calibrates and corrects drift, so the reading stays valid without calibration or removal throughout its service life.
Does it work with ester or silicone transformers?
Yes. It supports mineral oil, silicone, natural ester and synthetic ester; the liquid type is selected in the configuration software.
How long before the first reliable reading?
The unit runs its self-test and a start-up sequence once powered, and begins delivering valid readings on the day of installation.
How does it integrate with SCADA?
Through Modbus RTU or DNP3 on two-wire RS-485. Factory settings are Modbus address 1, DNP3 source 4 and destination 3, 19,200 baud and 8N1. A 4-20 mA signal is also available through the matching module.
Can it be fitted with the transformer in service?
It mounts on a 3/4" valve, following the bleed procedure that matches the sensor type. Installation must be carried out by qualified personnel authorised to work on the transformer.
