What kind of overhead line insulators

Advantages and disadvantages of the use of overhead line porcelain cross arm

Currently, many countries use more high voltage lines cross arm porcelain, China is also widely used. On 6 ~ 10 kV lines generally conical porcelain cross arm. Porcelain cross arm has the following advantages:

(1) due to the cross arm porcelain insulators and can double as cross arms, and the cost is low, so that is simplified line tower structure, but also has significant economic benefits.

(2) the level of mine-resistant insulation level and higher, good natural cleaning effect, the accident rate is low, use in polluted areas, the more reliable pin insulators.

(3) Since the porcelain cross arm is light, easy to clean, easy construction, maintenance and charging operations.

(4) Since the porcelain cross arm can automatically deflect a certain angle, if broken, may relax the wires themselves, prevent the accident. The main disadvantage of porcelain cross arm is lower than the mechanical strength of the iron cross arm, in the construction, transport easily damaged or broken. Thus, in the more sparsely used more rare place. If you improve the strength, or further to improve the material, the porcelain cross arm will be further popularized.

35 kV overhead lines mostly use suspension insulator pin insulator and rarely used current production of pin insulator, its performance is not stable enough to use easy to breakdown, aging, metal material consumption, large volume, and therefore rarely used . Suspension insulator iron cap, steel legs and porcelain composition, simple structure, high mechanical strength, low aging rate, according to the number of pieces needed to connect clusters, used in various voltage levels of transmission lines; suspension insulator disc diameter is small, the air discharge distance between the plates can be fully utilized. Therefore, the suspension insulator more widely used in overhead lines.

High voltage insulator surface made of corrugated role

High voltage insulator made convex and concave surface corrugations can cause the following effects:

(1) extending the length of the arc to climb in the same effective height, increasing the arc climb arc distance, and each can play a blocking arc ripple effect, increasing sliding flashover voltage insulator.

(2) in a heavy rain, heavy rain washed down the sewage can not flow directly from the lower portion of the upper portion of the insulator is formed of water caused by a short circuit to ground, corrugated insulator played a role in blocking the flow of water.

(3) dust and dirt land on the insulator in the concave portion of the uneven distribution of the insulator, so to some extent to ensure the compressive strength of the insulator.

Overhead line terminal rod insulators chance of damage higher end rod insulator is located at the end of the line, when the lightning invasion, the terminal pole reflection occurs, the most serious 2X Dare voltage linearly rod insulators withstand voltage side smaller than the voltage value, the higher the terminal rod insulators risk of damage.