Best Insulation Services Kolkata


The overhead power lines are mandatorily mounted with insulators to prevent the flow of unwanted and faulty current loads, through the poles. At Subham Enterprise, we deal with the best insulation services for the overhead power lines. We deal majorly with the following type of insulators:

  • Pin Insulators
  • Suspension Insulators
  • Strain Insulators
  • Shackle Insulators
Pin Insulators

Pin Insulators find its importance when it comes to electric distribution systems with a maximum extendable limit of 33 kV voltage level. The insulators are enabled with is a groove on the upper end for housing the conductor. They are secured on the cross arms of the pole so as to facilitate the carriage of power lines. While the conductor wire is passed through the groove of the insulator, it is also secured by binding it with the same wire as of the conductor itself. The insulation material of a pin insulator mainly comprises of porcelain material. However, glass or plastic can also be used as alternate variants. It is important to note that the pin insulators must be protected from rain. Because, the insulators remain exposed to environment, and water being a good conductor of electricity, allows the passage of current if the insulators are wet. The productivity of a pin insulator is only limited to a maximum of 33 kV only.

Suspension Insulators

For voltages above 33 kV, the pin insulators are found to be commercially unproductive. In certain cases, suspension insulators are used in overhead lines. A suspension insulator is made up of a series of porcelain discs connected to each other with metal links, which eventually forms a string. The bottom end of the suspension string is suspended with a line conductor which is then secured to cross-arm of the tower. The number of discs in a suspension insulation string depends on the working voltage. Each of the discs are designed for a low voltage, of about 11 kV. So depending upon the working voltage, the number of discs can be calculated and installed accordingly.

An added benefit of using suspension insulators are, if any of the disc is damaged, it can easily be replaced. The replacement of the entire string is not necessary. In case the working voltage needs to be increased, the required insulation can easily be provided by increasing the number of discs in the string. Being suspended by the strings, the line conductors run below the earthed cross arms of the tower. As a result, it provides partial protection from lightening during thunderstorms. The suspended insulators also provide added flexibility to the line. These type of insulators swings in the air and accordingly positions itself at areas with minimum mechanical stress.

Strain Insulators

The high voltage transmission lines are often subjected to high tensile load at the dead ends, corners or curves. For that reason, strain insulators are installed at those points. The strain insulators are comprised of an assembly of string insulators.However, the difference is, in this case, the suspension string of the insulators are arranged horizontally, while the discs are placed in a vertical plane. Often, multiple strain insulators are combined and assembled to sustain greater tensile strengths.

Shackle Insulators

In case of low voltage transmission lines (usually less than 11 kV), shackle insulators serve the purpose as a strain insulator. These type of insulators can either be used vertically or horizontally. In fact, it can be directly connected to the pole with a bolt or via the cross arm. However, these type of insulators are rarely used nowadays, due to the emergence of increased use of underground cables.

Benefits of the insulators we deal with:
  • We deal with insulators of high mechanical strength, that are capable to withstand wing loads and high conductor loads.
  • Our insulators are enabled with high electrical resistance that minimizes the leakage currents.
  • The insulating materials of our insulator bears high relative permittivity. Eventually the dielectric strength remains high.
  • The insulators come with high ratio of puncture strength to flashover.
  • The insulators are protected from rain with the help of rain sheds.
  • The insulators are robust, seamless and extremely resistant to adverse weather conditions and calamities.
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