Insulators and how we classify them.
1. Insulators are classified according to the system voltage. This maybe 1Kv, 3Kv, 6KV, 11, KV, 20Kv, 33Kv, 66KV, 132Kv, 275Kv, 420Kv, and 500Kv. 2. They are also classified according to their position or “configuration” when insulating the conductor from the structure eg. Post type, suspension, tension, cantilever. So therefore insulators have to have two duites: Electrical duties to withstand the system voltage. Mechanical duties to withstand the forces in the conductor string.
3. In all Insulators there is the solid core which withstands the mechanical forces, and the shed of the insulator which withstands the electrical forces or voltages. 4. Insulators have to “fit” within a design size in the overhead line. So the length of the insulator can be very important. 5. If it is a post or cantilever insulator it has to withstand big bending forces and we have to have bigger diameters the larger the bending forces. In composite insulators the larger the bending force the bigger size of rod. So if the bending force is 8Kn and the length of insulator is say 6. Often a designer will choose the insulator to have a tensile strength of say 120Kn, This high strength is not possible for a post insulator so the insulator chosen will be in tension or suspension. 7. The higher the system voltage, the greater the creepage and the impulse level of the insulator. 8. The purpose of the insulator is to insulate the conductor from the structure that supports the conductors or conductors. This is purely an electrical requirement. Sometimes the designer will specify many electrical parameters but always starting with the impulse level that the insulator has to withstand. 9. There are about 6 electrical requirements that the designer has to think about. I can show you and tell you what these are according to IEC 61606. 10. Sometimes there maybe environmental factors such as altitude, low temperature, snow fall, fog or heavy rainfall all which have to be considered in insulator design. 更多资料见 , |
