Hydrogen is used to cool the bearings and other rotating parts of large stationary electric generators. Hydrogen has a high thermal conductivity which provides very efficient heat transfer from the generator. Additionally, due to its low viscosity, the losses due to wind resistance are reduced when using hydrogen gas as a coolant. Contamination of the hydrogen can adversely impact its ability to cool the generator, decrease generator operating efficiency, and potentially causes damage to the generator.
Moisture contamination reduces the thermal conductivity and increases the viscosity of hydrogen. Moisture can also cause arcing, which can damage the generator windings. Ingress of moisture into the electrical generator may be due to inefficient drying of the hydrogen gas, a leak in a heat exchange, contamination of the lubricating seal oil, or poor purging after maintenance. Therefore, it is critical to measure the moisture content of the hydrogen gas in the hydrogen-cooled electric generator.
Operators have options when choosing moisture analysis equipment. Lithium chloride hygrometers, in-line psychrometers, electrolytic moisture sensors, and aluminum oxide probes have all proven to be high maintenance, slow to respond to changes in the moisture content, or inaccurate. A better option is quartz crystal microbalance (QCM) technology.
With a QCM-based analyzer, the actual moisture concentration in the cooling gas is easily and accurately measurable. These analyzers are highly accurate, fast responding to changes in moisture content, do not require annual factory calibration, and have the ability to self-verify or self-calibrate, providing the operator with confidence in a reliable moisture reading.
Learn more about QCM-based technology and AMETEK analyzer options.