Vaisala - Measuring Instruments for the Power Industry

Vaisala offers a range of premium measurement technologies and stable measurement equipment that help to optimize operational performance and cost-efficient maintenance.

With over 75 years of experience, close to 30 offices worldwide and thousands of customers in over 120 countries, we are known as a leader in developing, manufacturing and servicing high-quality measuring instruments for the power industry.

Our products provide stable and reliable measurements of relative humidity, dew point, moisture-in-oil temperature, SF density and pressure. The measuring can be done real-time, online or periodicly spot-checking. Accurate measuring helps to extend the lifetime of critical high-voltage assets, maximize performance and yield and minimize risks.

On-line monitoring of moisture in transformer oil

Moisture reduces the insulating properties of transformer oil and quickens the ageing of the insulating cellulose. Traditionally, oil moisture readings have been checked periodically. However, the moisture levels can change rapidly and considerably, and therefore a sampling method may not be sufficient. To ensure timely, cost-efficient maintenance, a permanent on-line monitoring system is needed.

Moisture and temperature transmitters for oil

Vaisala's MMT330 moisture and temperature transmitter series for oil accurately measures moisture in transformer oil on-line, giving a real-time picture of the oil's condition, and thus the transformer condition. The moisture levels can be monitored at all ambient and operating conditions the transformer is exposed to. On-line monitoring is one tool in aiding temporary overloading of the transformer safely and enables timely preventive-maintenance actions.

The Vaisala moisture-in-oil transmitter works at all ambient and operating conditions. It is compatible with any insulating oil and works independently of oil age and temperature.

Long-term stability is ensured by the Vaisala-designed HUMICAP® sensor, the first sensor ever to measure moisture in oil on-line. The innovative, chemical-resistant HUMICAP® sensor has proven itself even in the most demanding conditions.

For temporary spot-checking there is also a lightweight handheld meter, the MM70.

Online monitoring of SF6 gas density, moisture, temperature and pressure

In order to maintain SF6 insulation properties and reduce the formation of unwanted secondary decomposition products, the amount of water vapour in the gas insulated system (GIS) should be kept to a minimum. Also, the SF6 system needs to be pressure-tight for best insulation performance and safe operation of equipment.

The new Vaisala Multiparameter Transmitter DPT145 for SF6 Gas is a unique innovation that measures dew point, pressure and temperature, and calculates four others including SF6 density. Getting seven parameters online with one meter saves time and money across the board from investment to installation, operation and service. While online monitoring helps minimize onsite visits, it also removes the need for sampling and ensures that no SF6 gas is released into the atmosphere. The direct normalized pressure value offers fast leakage detection.

Spot-check convenience with the DM70 Hand-Held

When SF6 dew point spot-checks are required, the Vaisala DRYCAP Hand-Held Dewpoint Meter DM70 is the optimal lightweight, battery-powered instrument for the job. Fast response time and internal data-logging minimise the amount of SF6 needed for sampling and optimise the field technician's time. The sampling cells available are optimised for measurement in the SF6-gas-insulated equipment, enabling measurement at both gas system and atmospheric pressure. The sampling cells also enable collection and recycling of SF6 when measuring in atmospheric pressure.

Humidity-monitoring equipment for turbine inlet air

Accurate humidity measurement of inlet air is essential for turbine controlling. The cooler the air the better the yield of the turbine, as when the temperature decreases the density of the air increases. This results in a greater mass of air flowing through the turbine, resulting in higher power generation. A 1ºC difference in temperature may mean a 0.5% electricity loss.

However, air that is too cold or humid must be avoided as it may lead to water condensation or even icing, which damages the turbine blades. With reliable humidity monitoring the utility operator can cool and compress the inlet air, maximising the power generation without risking condensation.

Humidity and temperature transmitters

The HMT330 humidity and temperature transmitter series incorporates Vaisala's 30 years of experience in industrial humidity measurement. For operators in the power industry this means reliable, stable and accurate measurements.

With the HMT330 series you have versatile options to choose from: numerical and graphical display, a multi-lingual menu, alarms, trends, one-year history, and WLAN/LAN.

Humidity and temperature transmitters for hydrogen-cooled generators

Dry hydrogen is used for cooling of electric generators because of its high thermal conductivity and low viscosity. Increasing moisture in the hydrogen may lead to decreased cooling efficiency, decreased insulation capability and corrosion of generator parts, in the worst case leading to a breakdown of the generator.

Vaisala's intrinsically safe HMT360 humidity and temperature transmitter series is ideal for monitoring the performance of the dryer. The measurements can ensure that dry hydrogen is being fed to the generator. The sensor can also be installed directly into a pressurised pipeline.