RDP-206

SF₆ Dew Point Hygrometer

A chilled mirror dew point instrument optimized for SF₆ measurement, minimizing phase transition effects for reliable moisture verification.

Reliable Moisture Measurement for SF₆ Gas Systems

The RDP-206 SF₆ Dew Point Hygrometer is a chilled mirror instrument designed for accurate moisture measurement in SF₆ gas and SF₆-containing gas mixtures used in high-voltage power equipment.

The instrument provides stable dew point monitoring for GIS substations, circuit breakers, and gas-insulated transmission systems, supporting equipment commissioning, maintenance, and gas quality verification.

The measurement system and control strategy are optimized to minimize the influence of SF₆ phase transitions, ensuring reliable measurements under practical gas sampling conditions.

Key Features

• Primary chilled mirror dew point measurement principle
Direct thermodynamic measurement with high accuracy and no sensor drift.

• Optimized for SF₆ gas systems
Designed for reliable moisture measurement in SF₆ and SF₆ gas mixtures used in power equipment.

• Minimized influence from SF₆ phase transitions
Measurement design reduces the effects of gas phase behavior during sampling.

• Optimized temperature control and measurement dynamics
Advanced control strategy significantly reduces the risk of SF₆ phase transitions during measurement.

• Stable performance under field sampling conditions
Reliable measurements during substation maintenance, commissioning, and gas handling operations.

Measurement Range

Down to −55 °C dew point

The measurement range is optimized for typical moisture levels in SF₆ gas-insulated power equipment.

Extremely low mirror temperatures are avoided to reduce the possibility of SF₆ phase transitions, ensuring stable and repeatable measurements.

Typical Applications

High-Voltage Power Industry

• GIS substations

• GIS manufacturing and commissioning

• Circuit breaker maintenance and testing

• SF₆ gas recycling and purification systems

Measurement Principle

The RDP-206 uses the chilled mirror condensation principle, recognized as the primary thermodynamic method for dew point measurement.

Compared with polymer or aluminum-oxide humidity sensors, chilled mirror instruments provide:

• Primary measurement accuracy
• No long-term sensor drift
• Excellent repeatability and stability

This makes the instrument particularly suitable for critical moisture measurements in SF₆ systems.

Compatible Gases

The RDP-206 can measure moisture in:

• SF₆
• SF₆ / N₂ mixtures
• SF₆ / CF₄ mixtures
• SF₆ alternative insulation gases

Designed for SF₆ Measurement

Moisture measurement in SF₆ environments presents unique technical challenges.

Under certain pressure and temperature conditions, SF₆ gas may undergo phase transitions, which can influence gas equilibrium and sampling behavior.

The RDP-206 system is designed to minimize the influence of these effects, ensuring stable dew point measurements in both pure SF₆ and SF₆ gas mixtures.

Need Help Selecting the Right Instrument?

Our engineering team can help you select the most suitable instrument for your SF₆ moisture measurement application.