Precision dew point meter refers to a mirror dew point meter with semiconductor refrigeration and photoelectric automatic balance. Relative humidity is the percentage of the mole fraction of water vapor in the measured environment to the mole fraction of saturated water vapor at the same temperature and pressure, that is, the ratio of the partial pressure of water vapor in the environment to the saturated water vapor pressure at the same temperature (water vapor in the air). is equal to the saturated water vapor pressure at the dew point temperature). The precision dew point meter measures relative humidity by measuring dew point and ambient temperature, so relative humidity has two uncertain factors: the uncertainty of dew point and ambient temperature measurement.

The precision dew point meter should be placed in a safe place to prevent damage. Avoid violent vibrations. Do not measure corrosive gases. The probe should be cleaned and calibrated after a certain period of time, and the calibration cycle should be one year apart.

When calibration is required, adjust the gas flow and slowly open the needle valve so that the flow indication is 0.5-0.6 L/min. If the flow rate exceeds 1 L/min. At this point, the flow rate should be reduced to the specified value. (Excessive flow rates can damage the electronic flow sensor). After the instrument has been used for one day (using the battery), it should be charged in time. When charging, just connect the power cord to the 220V socket, the instrument will automatically charge, and the charging time is generally more than 5 hours.

The importance of moisture measurement with precision dew point meter Moisture is an important factor affecting insulation aging. Excessive moisture content will reduce the insulating properties of insulating materials and accelerate their aging, so the main source of moisture inside electrical equipment:

(1) External intrusion: It is caused by improper protective measures during equipment manufacturing, transportation and installation. (2) Autogenous: the water produced by the oxidation cracking of the insulating medium during the operation of the equipment. For hydrogen-cooled units, high hydrogen humidity is one of the main factors affecting the safe operation of generators.

With the continuous production of large-capacity and high-parameter units, there have been many vicious accidents in which the hydrogen humidity exceeds the standard and burns the generator. The accurate measurement of traditional hygrometer parameters can no longer ensure the safe operation of the equipment and cannot meet the needs of the power system. Precision dew point instrument micro water (humidity) measurement method SF6 gas humidity measurement For the measurement of SF6 gas humidity, the commonly used methods are gravimetric method and Coulomb electrolysis method. The method pair has higher requirements on environmental conditions and long measurement time, and is generally only used for arbitration analysis; method 2 consumes a large amount of gas during measurement, and the equipment needs to be energized and dried for many years when it is not in use, and the repeatability is poor. The measurement of H2 humidity usually includes ventilation dry and wet bulb method and Coulomb electrolysis method. The first method is greatly affected by the ambient temperature and humidity, and the measured value is higher; the second method not only has the above shortcomings, but also is afraid of pollution.