High-voltage power equipment

  • Categories:Applications
  • Time of issue:2020-11-27 17:40:05
  • Views:0
The vacuum interrupter is the core key component in the power switch. The switch composed of this product and circuit breaker, load switch, contactor, recloser, sectioner, etc. has the characteristics of small size, strong breaking capacity, long life, energy saving and explosion-proof, no pollution, and low maintenance cost. It is widely used in power supply control systems for power grids, petrochemicals, metallurgy, mines, high-speed railways, communications and high-rise buildings.
The vacuum interrupter is an electric vacuum device that uses high vacuum as an insulating medium and uses a pair of contacts sealed in the vacuum to realize the on and off functions of the power circuit. The basic structure is shown in the schematic diagram. When it disconnects a certain value of current, at the moment when the moving and fixed contacts are separated, the current shrinks to a certain point or a few points where the contacts just separated, the resistance between the electrodes increases sharply and the temperature rises rapidly, until the electrode metal At the same time, there is a strong electric field between the contacts, resulting in violent field emission and ionization of the metal vapor, resulting in a vacuum arc; when the AC current is close to zero, the metal vapor will almost stop evaporating, and the vacuum arc plasma The body quickly spreads around, the arc is extinguished, and the medium in the contact gap quickly changes from a conductor to an insulator, so the current is broken and the breaking ends.
        1. Conditions of use
        1.1 The altitude does not exceed 1000 meters (except for special requirements).
        1.2 Ambient temperature: indoor -25°C~40°C, outdoor -40°C~40°C.
        1.3 Indoor relative humidity, the daily average is not more than 95%RH, and the monthly average is not more than 90%RH. Outdoors, there should be corresponding anti-condensation measures.
        1.4 The earthquake intensity does not exceed 8 levels.
        1.5 There is no place with fire, explosion, serious pollution, chemical corrosion and severe vibration.
        1.6 When used for switching capacitive and inductive loads such as capacitor banks, high-voltage motors, arc furnace transformers, etc., corresponding overvoltage protection measures should be adopted. Among them, it is recommended to give priority to resistance-capacitance protection for inductive loads.
        2. Inspection and acceptance
        2.1 Check whether the packaging is intact. After opening the box, check whether the appearance of the arc extinguishing chamber is intact and whether the parameters on the product nameplate are consistent with the certificate.
        2.2 The vacuum interrupter shall be subjected to a power frequency withstand voltage test before use. Before the test, use a dry cloth or a clean cloth moistened with alcohol to clean the surface. The test specification is: in the rated distance, add 70% of the rated power frequency withstand voltage at both ends, stabilize for one minute, and then rise to the rated power frequency withstand voltage within one minute, keep it for one minute, indicating that the indicator pointer is not Sudden change and tripping are qualified. Sporadic fires and other slight light and flicker phenomena are allowed in the tube.
        2.3 After the above inspection, if the interrupter is judged to be unqualified, please contact the marketing department of our company in time for timely treatment.
        3. Precautions during installation and debugging
        3.1 Before installing the vacuum interrupter, use cotton cloth or silk cloth with a little alcohol to wipe clean the surface of the insulation shell of the interrupter. At the same time, clean the conductive rod and the electrical connection surface to make it have good contact with the whole machine. Electrical contact.
        3.2 After installing the vacuum interrupter, adjust the mechanical parameters as required. The mechanical parameters related to the vacuum interrupter should meet the parameter requirements given in the technical conditions.
        3.3 The vacuum interrupter must have a guiding device when it is working, so that the coaxiality of the moving conductive rod to the axis of the entire tube meets the requirements, and the bellows is not subject to torsion.
        3.4 It is strictly forbidden to hit or knock the vacuum interrupter shell with hard objects during installation to prevent it from being broken and leaking, and at the same time to prevent the insulation shell from being scratched, otherwise it will be easily broken after being heated and heated during use.
        3.5 Pay attention to ensure the coaxiality of the conducting rod of the vacuum interrupter and the perpendicularity to the static end surface.
        3.6 Be careful not to repeatedly disassemble the vacuum interrupter to prevent the screw hole sliding buckle. It is strictly forbidden to twist the conductive rod or excessively compress the bellows, so as to avoid torsion and scratches on the bellows, affect the service life or cause air leakage in the vacuum interrupter Invalidate.
        3.7 During installation, pay attention that the force applied on both ends of the vacuum interrupter should not exceed the static safety pressure specified in the product technical conditions.
        3.8 When the static end of the vacuum interrupter is installed, the screw depth of the fastening screw plate should be less than the calibrated depth of the screw hole to prevent top damage to the cover plate and damage to the vacuum interrupter by air leakage. When tightening screws, they should be tightened symmetrically and evenly.
        3.9 When assembling the insulated pull rod, ensure that the effective depth of the precession conductive rod is not less than 1.5 times the nominal diameter of the thread.
        3.10 During the installation process, the insulating shell and ceramic seal of the vacuum interrupter should not be subjected to obvious lateral force.
        4. Use and maintenance
        4.1 During use, the vacuum degree of the vacuum interrupter should be checked regularly by the power frequency withstand voltage method. See 2.2 for the method.
        4.2 Regularly check the contact burnout of the vacuum interrupter. When the burnout mark of the movable conductive rod is reached or the thickness of the burnout exceeds the standard value, it indicates that the electrical life of the vacuum interrupter has expired and should be replaced.
        4.3 If the vacuum interrupter is not used for a long time, it must be checked regularly. If it is corroded by water vapor and harmful gases, it should be cleaned. If the vacuum interrupter is found to be damp, place it in an oven at 70°C-80°C for 48 hours before using it.
        4.4 During the use of the vacuum interrupter, the enclosure should be kept clean and dry to avoid lowering the insulation level.
        5. Accessories, packaging, transportation and storage
        5.1 One installation manual and one certificate.
        5.2 When the vacuum interrupter leaves the factory, it should be packaged in accordance with the specified packaging standards, with clear and eye-catching signs such as "upward", "beware of moisture", and "handle with care".
        5.3 The packaged vacuum interrupter can be transported by car, train or airplane. In automobile transportation, the allowable degree of turbulence is equivalent to that of a car's third-level road at a speed of 20km/h. Handle with care during loading and unloading, and do not roll or collide.
        5.4 The vacuum interrupter should be stored in a ventilated, dry, and non-corrosive gas room. From the date of delivery, the storage period is 20 years in a suitable storage environment.

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