1. First, turn on the power. The instrument will perform self-calibration first, and after self-calibration is completed, it enters the measurement state.
2. While the instrument is self-calibrating, connect the test pipeline provided with the instrument to the switch connector of the switch to be measured, and then connect the switch connector to the switch under test.
3. Close the flow regulating valve, and connect the test pipeline to the air inlet of the instrument. At this time, the pressure displayed on the screen is the gas pressure inside the switch under test.
4. Start measurement: open the flow regulating valve, adjust the flow to about 0.5 L/min, and do not exceed 0.8 L/min at maximum. This enters the measurement state. The measurement time is about 8 minutes (for the first device).
5. At the end of measurement, if you need to print data, simply press the print key, enter the device number to be measured, then press the confirm key, and the instrument will start printing. Finally, close the flow regulating valve, remove the test pipeline from the instrument air inlet, and finally remove the switch connector.
6. Turn off the power. Put away the test pipeline and switch connector. The entire measurement is complete.
Usage Precautions
● The instrument should be placed in a safe position to prevent falling and damage. Avoid severe vibration.
● Do not measure corrosive gases.
● The probe should be cleaned and calibrated after a certain period of use. The calibration interval is one year. When calibration is needed, please contact our company.
● When adjusting the gas flow, open the needle valve slowly so that the flow indication is between 0.5-0.6 L/min. If the flow exceeds 1 L/min, the LCD will display a flow over-limit warning. At this time, reduce the flow to the specified value. (Excessive flow will damage the electronic flow sensor.)
● After using the instrument for one day (using battery), it should be charged promptly. To charge, simply connect the power cord to a 220V outlet. There is no need to turn on the power switch; the instrument will charge automatically. The charging time is generally more than 5 hours.
Importance of Moisture Measurement
Moisture is an important factor affecting insulation aging. Excessive moisture content can reduce the insulation performance of insulating materials and accelerate their aging, thereby reducing the reliability of operating equipment and shortening its lifespan.
Main sources of moisture inside electrical equipment:
(1) External intrusion: caused by improper protective measures during manufacturing, transportation, and installation of equipment.
(2) Self-generation: moisture produced by oxidation and cracking of insulating media during equipment operation.
For hydrogen-cooled units, high hydrogen humidity is one of the main factors affecting the safe operation of generators. With the continuous commissioning of large-capacity, high-parameter units, multiple serious accidents have occurred domestically where generator units were burned due to hydrogen humidity exceeding standards. The accuracy of traditional hygrometer parameter measurement can no longer ensure the safe operation of equipment and cannot meet the needs of the power system.
Micro Moisture (Humidity) Measurement Methods
◆Measurement of SF6 Gas Humidity
For the measurement of SF6 gas humidity, common methods include the gravimetric method and the coulometric electrolysis method. The first method has relatively high requirements on environmental conditions and takes a long time to measure; it is generally only used for arbitration analysis. The second method consumes a large amount of gas during measurement, requires the equipment to be powered on for drying all year round when not in use, and has poor repeatability.
◆Measurement of H2 Humidity
Common measurement methods include the ventilated wet-bulb method and the coulometric electrolysis method. The first method is greatly affected by ambient temperature and humidity, and the measured value tends to be high. The second method, in addition to the aforementioned disadvantages, is also susceptible to contamination, etc.
