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

It features Vaisala's DryCap® and BaroCap® sensor, manufactured in clean rooms at our factory in Finland. The DryCap® is specifically designed for dew point measurement, and has several functions to ensure accurate measurement for years without significant variation. The BaroCap® is a proven sensor used as a standard in the barometric pressure measurement industry.
The DPT is IP66 and "high pressure leak tested" at the factory, arriving complete and ready for quick installation. An environmental shield option is available for additional protection in outdoor or wetter environments.

Uses and Applications:

The electrical industry uses SF6 gas to insulate switchgear, 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 by-products from gas decomposition, which can cause electrical arcing and equipment failure.

For on-line monitoring of SF6 gas, Vaisala offers the DPT145 Multi-Parameter Transmitter. This equipment allows online measurement of dew point, pressure and temperature in addition to four other values, including SF6 density.

Minor and sudden leaks are detected immediately through direct measurement of normalized pressure, while the in-line dew point measurement warns the user of problems with moisture, which can weaken the insulation properties of SF6 and cause rapid deterioration of equipment.

In-line measurement combined with a data acquisition system allows tracking gas trends, making SF6 monitoring fast, accurate and risk-free. Using a single instrument to monitor seven different parameters also means fewer mechanical connections and reduced leakage. The monitoring is environmentally friendly since no samples need to be taken, eliminating the risk of SF6 gas being released into the atmosphere.

The use of a single transmitter, instead of several, saves time and money in all areas of the investment - in installation, operation and maintenance of the equipment. Low mounting costs, less wiring and connectors, minimizes the need for site visits and field operations resulting in cumulative savings.

Advantages:

• First transmitter to offer 7 parameters in a single device
  Direct Measurements: Spray Point, Pressure, Temperature
  Calculated measurements: SF6 density, normalized pressure, atmospheric dew point, humidity in ppm.
• Saves time and money in all areas of investment: installation, operation and maintenance of equipment.
• SF6 condition assessment by having continuous real time measurement
• Calibration interval in years.
• Digital communication protocols, including RS-485 with MODBUS