LGQDG pneumatic single-phase isolation switch
Model and its meaning
Technical parameters
The main technical parameters of the disconnecting switch are shown in Table 1.
| model | Rated voltage (kV) | Maximum operating voltage (KV) | Rated current (A) | Operating pressure (MPa) |
| LGQDG-12 | 12 | 1.3 times the rated voltage | 400~8000 | 0.7±0.1 |
| LGQDG-20 | 20 | 1.3 times the rated voltage | 0.7±0.1 | |
| LGQDG-40.5 | 40.5 | 1.3 times the rated voltage | 0.7±0.1 | |
| LGQDG-110 | 110 | 1.3 times the rated voltage | 0.7±0.1 | |
| LGQDG-145 | 145 | 1.3 times the rated voltage | 0.7±0.1 |
Preparations before installation
1. After unpacking, check the product spare parts and accompanying technical documents against the packing list to see if they are complete, and check whether the product has been damaged during transportation and storage.
2. Remove dirt and dust from the product, and carefully wipe the surfaces of the insulators and contact parts.
3. Apply industrial petroleum jelly (neutral) to all rotating contact parts of the machine.
Note: This series of products generally only allows vertical or horizontal installation. If tilted or inverted (hanging) installation is required, special manufacturing must be carried out in consultation with the manufacturer. However, regardless of the installation method, the isolation distance of the switch (which shall be negotiated between the user and the manufacturer) and reliable locking in the working position and isolation position must be guaranteed.
Product outline drawing
Structure and working principle of pneumatic disconnect switch
This series of single-phase disconnect switches uses different cylinders for operation according to different voltage levels and current magnitudes to achieve the purpose of opening and closing. Each cylinder is equipped with an adjustment joint to adjust the opening and closing speed of the switch. The adjustment joint has a connector for connecting the air circuit pipe; simply insert a pipe of the appropriate diameter.
The specified operating air pressure for this series of products is 0.7±0.1Mpa, with a minimum permissible operating air pressure of 0.5Mpa (for factory testing only, not for normal operation). All insulators in this series are made of porcelain with large creepage distance. The insulating rods for 12KV products are made of epoxy glass cloth, while those for 40.5KV and above are made of silicone rubber. All contacts and terminals are made of profiles with line contact, which ensures good contact, reduces operating force, and improves rotational flexibility.
Environmental conditions for use
1. Ambient air temperature: upper limit +40°C, lower limit -10°C; Note: Storage and transportation are permitted at -25°C.
2. Altitude: 1000 meters (general type) and 3000 meters (alpine type).
3. Humidity: Relative temperature: Daily average not greater than 95%, monthly average not greater than 90%.
4. The surrounding air should not be significantly polluted by corrosive or flammable gases, water vapor, etc.
5. No frequent, severe vibrations.
Use, maintenance and repair
1. Disconnect switches must be inspected only after the power supply has been disconnected, i.e., when they are not energized. If connected to a capacitor bank, the grounding wire of the connected capacitor bank must be connected.
To prevent the capacitor from storing too much electrical energy and causing injury or death, place it on the container.
2. During the maintenance of disconnecting switches, carefully inspect the insulators for damage and check whether the contacts are making good contact.
3. Polish the damaged parts of the contacts with fine sandpaper to remove dust, especially the conductive parts and the surface of the insulators. After the maintenance is completed, apply a layer of industrial neutral petroleum jelly to the contact area.
4. Check that the fasteners are secure and that the grounding is in good condition. Do not allow the grounding screws to be loose or for any rust to be present at the contact points.
5. Inspect the contacts and contact blades. If there is serious damage or permanent deformation of the pressure spring, they must be replaced before use.
6. After all maintenance and installation are completed, 10 separate and combined silo tests must be conducted. If the test does not meet the requirements, readjustment is still required. The silo can only be put into operation after passing the test.
7. The disconnecting switch should be wiped clean once a month and thoroughly inspected and maintained once a quarter to ensure its normal operation.