The DPT145 provides in-line dew point and pressure measurements and offers an excellent assessment of the condition of SF6 gas insulation through a total of 7 parameters, including density and H2O ppm.

It features Vaisala’s DryCap® and BaroCap® sensors, manufactured in the cleanrooms at our factory in Finland. The DryCap® is specifically designed for dew point measurement and includes several features to ensure accurate measurements for years without significant variation. The BaroCap® is a proven sensor that serves as the industry standard for barometric pressure measurements.
The DPT is IP66-rated and “high-pressure leak-tested” at the factory, arriving fully assembled and ready for quick installation. An environmental shield is available as an option for additional protection in outdoor or wetter environments.

Uses and Applications:

The electric power industry uses SF6 gas to insulate distribution devices, circuit breakers, and other equipment used in the transmission and distribution of electricity. To ensure the integrity of SF6 gas as an insulator, the amount of water vapor in the SF6 gas must be minimal. Moisture can increase the formation of unwanted byproducts resulting from gas decomposition, which can cause electrical arcing and equipment failure.

For online monitoring of SF6 gas, Vaisala offers the DPT145 multi-parameter transmitter. This device enables online measurement of dew point, pressure, and temperature, as well as four other parameters, including SF6 density.

Minor and sudden leaks are detected immediately through direct measurement of normalized pressure, while in-line dew point measurement alerts the user to moisture-related issues, which can weaken the insulating properties of SF6 and cause rapid deterioration of the equipment.

Online measurement combined with a data acquisition system allows for tracking gas trends, enabling fast, accurate, and risk-free SF6 monitoring. Using a single instrument to monitor seven different parameters also means fewer mechanical connections and fewer leaks. The monitoring process is environmentally friendly since no sampling is required, eliminating the risk of SF6 gas being released into the atmosphere.

Using a single transmitter, rather than multiple ones, saves time and money across all aspects of the investment—including equipment installation, operation, and maintenance. Low installation costs, less wiring and fewer connectors minimize the need for site visits and field operations, resulting in cumulative savings.

Advantages:

• The first transmitter to offer 7 parameters in a single unit
  Direct Measurements: Dew Point, Pressure, Temperature
  Calculated measurements: SF6 density, normalized pressure, atmospheric dew point, humidity in ppm
• Save time and money in all areas of investment: installation, operation, and maintenance of equipment
• SF6 Status Monitoring Through Continuous Real-Time Measurement
• Calibration interval in years.
• Digital communication protocols, including RS-485 with MODBUS