Stuttgarter Hochspannungssymposium 2022

Power Generation and Transmission

Meet our experts at the Stuttgarter Hochspannungssymposium 2022 to discuss Vaisala solutions for DGA monitoring.

Read more on: Stuttgarter Hochspannungssymposium 2022

Benefits of Vaisala’s DGA Monitoring Technology


High gas extraction rate, novel vacuum IR reference method and patented autocalibration leads to more reliable results and excellent long-term stability.

Long Lifetime

Maintenance free operation through robust design and hermetic metal structure of the oil and gas handling system. 

No moving parts in the optical IR measurement module.

No consumables and no gas cylinders.

Out of the Box Performance

Online DGA monitoring provides real time view of the transformers condition.

Enabling corrective actions taken on time.

Watch the video

Maintenance free monitoring with the Vaisala Optimus™ OPT100 DGA


Vaisala offers a range of specialized online measurement equipment for the power industry. The reliable online measurement of dissolved gases and moisture in transformer oil, dew point, humidity, density, temperature, and pressure helps to ensure that high-voltage assets can operate at maximum efficiency while supporting the planning of predictive maintenance designed to extend asset lifetime and minimize unexpected outages.

Senja Leivo

Expert Insight: Online DGA Monitoring of Power Transformers

Do you know the key fault gases and why they form in transformers?

Find the fundamentals of dissolved gas analysis for power transformers and get to know the data from field tests of Vaisala online monitors. 

Explore Vaisala Power Instruments and Services Offering. Download now and utilize tips from our experts to improve your business.

Vaisala Humicap sensor structure

Uniquely robust sensors

Vaisala’s HUMICAP® were the first ever capacitive sensors used to measure moisture in oil online, and have since become a virtual industry standard. 

The sensors have specifically been developed to measure even very low moisture levels in oils — mineral, vegetable and synthetic. The HUMICAP® sensors, manufactured in Vaisala’s own cleanrooms, have seen use in all corners of the Earth and even Mars.

Get all the gains

Robust reliability

  • Accurate water saturation and PPM measurements in rapidly changing conditions.
  • All equipment comes with NIST or Accredited calibration and is field calibratable.
  • No moving parts in transmitters.

Long-term stability

  • Thin film polymer sensor designs protect from contamination and are highly selective to water  only .
  • Capacitive technology provides long term stable measurement.
  • Insensitive to additives or contaminants in oil.
  • Auto-recovery from full saturation.

Rapid Response

  • In situ, real time measurement of moisture in oil as true relative saturation (%RS).
  • Eliminates need for sampling and lab analysis for moisture.
  • Easy installation via ball valve. 
  • Installable even in energized transformers.

Related Products for Moisture in Oil

Moisture in oil probe MMP8

MMP8 for Continuous Online Measurement​

Vaisala HUMICAP® Moisture in Oil Probe MMP8 enables fast and reliable measurement of moisture in oil.

MMT330 Moisture and Temperature Transmitter Series for Oil

Moisture and temperature transmitter MMT330

The MMT330 series enables fast and reliable detection of moisture in oil in central lubrication systems, hydraulic systems and power transformers. Three probe options offer solutions for various installation requirements, like high pressure, tight spaces and pipeline installations. The series is also compliant with DNV GL 2.4 type approval (Class B).

MMT162 Compact Moisture in Oil and Temperature Transmitter for OEM Applications

Moisture and Temperature Transmitter for Oil MMT162

Excellent economical solution for reliable on-line detection of moisture in oil even in the most demanding applications. The sensor’s excellent chemical tolerance provides accurate and reliable measurement over the measurement range.

MM70 Hand-Held Moisture and Temperature Meter for Spot-Checking in Oil

Hand-Held Moisture and Temperature Meter for Spot-Checking in Oil MM70

Reliable MM70 is an ideal tool for the preventive maintenance of oil-filled systems. The water activity measurement indicates the margin to free water formation, which causes severe problems in lubrication systems. Excellent pressure and temperature tolerance.

MMT310 Series Moisture and Temperature Transmitters for Oil

Moisture and Temperature Meter Series MMT310

Vaisala HUMICAP® Moisture and Temperature Transmitter Series MMT310 is a fast and reliable on-line detector for moisture in oil. Used in for applications such as e.g. monitoring of transformer oil and of lubrication systems in marine and paper industry.

Monitor Transformer Oil with MHT410

Moisture, Hydrogen and Temperature Transmitter MHT410

Single-gas monitor as early warning indicator of a fault condition.

Vaisala’s Optimus™ DGA Monitor OPT100 for advanced dissolved gas analysis with total gas pressure method, detecting air leaks in transformers.

Optimus™ DGA Monitor OPT100

Multi-gas monitor for critical power transformers online monitoring.