Since the inception of silicone insulators for high voltage and medium voltage electrical applications, they have revolutionized the power transmission systems.
Since the inception of silicone insulators for high voltage and medium voltage electrical applications, they have revolutionized the power transmission systems. Since, most of these systems are of over head type, the insulators employed here should combat several odds. The design and materials employed in these insulators can vary with the line voltage, environmental conditions and others. Here under, we detail you the construction of high voltage silicone insulators:
End fitting:
Cast steel made end fittings are employed to for power distribution levels which are under 70 kN and for even higher levels, forged steel is used in end fittings. In special type of applications like power distribution across railway lines coquille aluminum which has a higher strength is used. These end fittings are galvanized by hot dipping method. Depending upon the chances of being corroded in the work area, the thickness of this coating is determined.
Rod:
This component of the insulator is made from the resin rod which is reinforced by the glass fiber. In general, these rods are produced by continuous pultrusion process. The type of application determines the diameter of the rods. The mechanical properties induced into these rods are imparted by the content in them. It is important to choose appropriate size of the glass as it affects the bond between of the composite materials. An ideal resin matrix should absorb least moisture and retain its mechanical and electrical properties under any adverse conditions. Unequal elongation of the resin and the glass can result in cracks. The design and construction is so made that they expand equally. As of now, epoxy made resin is extensively used in HV power distribution systems. The rods are designed and fabricated distinctly to meet the needs of tension and bending applications.
Housing:
The ultimate purpose of the insulator is to eliminate any sort of flashover caused by pollution or intense voltage levels. Since the polymers have successfully replaced the porcelain ware, many trails were conducted to get to know the perfect polymers for the job. It is inferred that the properties of the polymer used should be considered strongly while designing the insulator. Among the many available polymers, silicone rubber insulators are highly preferred as they are durable and offer a reliable performance. The design of the insulator and the wetting properties of the housing are the crucial factors to access their pollution performance.
In comparison to many other polymeric materials, silicones have proven that they have the best at the job. The silicone made insulators have excellent hydrophobicity and anti-aging properties. Hydrophobicity refers to the non-wetting properties of the substance. One of the biggest problems in these insulators, surface contamination is effectively handled with silicone. This property ensures good performance of the insulator under polluted conditions and also eliminates the need for the regular cleaning and maintenance activities. In due course of time, even if the silicone insulator tends to lose this property, a secondary protection is readily available for the insulator. Prolonged usage can lead to tracking and bulk erosion. The silicone material has inherent anti-aging properties, which can deal effectively with tracking and erosion.