The Best Insulator for your Substation

By definition, an insulator is a material that resists the flow of electric current. An insulating material has atoms with tightly bonded valence electrons. These materials are used in parts of electrical equipment, also called insulators, intended to support or separate electrical conductors without passing current through themselves. The term is also used more specifically to refer to insulating supports that attach electric power transmission wires to utility poles.

An insulator is typically comprised of an insulating core that extends between two electrodes which are maintained at significantly different electrical potentials. Insulators have been made with various materials. High voltage electrical insulators for use at voltages in excess of about 1000 volts, and typically at 34.5kV, can be made from porcelain, glass fibre, or solid polymeric material.

Porcelain insulators have outstanding electrical properties and are the preferred insulator for utility substations. Porcelain insulators offer much higher load-bearing ratings over glass and polymer insulators. Porcelain insulators are made from clay, or alumina, and are covered with a smooth glaze (typically gray or brown) to shed water.

While glass has a higher dielectric strength than porcelain, it attracts condensation and the thick irregular shapes needed for insulators are difficult to cast and manufacture without internal strains. Some insulator manufacturers stopped making glass insulators in the late 1960s, switching to ceramic/porcelain materials.

Recently, some electric utilities have begun converting to polymer composite materials for some types of insulators. These are typically composed of a central rod made of fibre reinforced plastic and an outer weathershed made of silicone rubber or EPDM. Composite insulators are less costly, lighter in weight, and have good hydrophobic capability. This combination makes them ideal for service in polluted areas. However, these materials do not yet have the long-term proven service life of porcelain insulators.

Porcelain insulators were constructed as early as the 1850s, but glass was still more popular since it was more affordable, however electricity was not what it is today. About thirty years later, electricity was being distributed in higher voltages and porcelain proved to be better fit for the job. Many insulator manufacturers stopped making glass insulators in the late 1960s after switching to ceramic ones.

Porcelain can be used to create bushings; the hallow insulators that have a conductor inside of them. Some other electrical products include indoor porcelain bus insulators, indoor standoff insulators, and station post insulators. If your current glass insulators are doing the job, consider making the switch to the higher quality porcelain products to improve the efficiency of your business.

Such products are made from the highest quality of wet porcelain, which is a method used to prevent cracking in the insulator. These porcelain insulators provide strength and the long life for reliable substation operation as well as providing maximum economy. Making the switch from glass to porcelain has many advantages such as reducing electrical consumption and making efficient use of the energy already being consumed. This electrical switch would be considered a smart, green industrial upgrade for your company.

Other advantages to using porcelain electrical products include stability, material strength, low cost, and earthquake resistance. Since porcelain insulators have been in use for more than 100 years, they have proven to be resistant to environmental aging. Porcelain is stable in its structure and will not be damaged by environmental stresses such as humidity, UV light, or electrical activity. Although porcelain insulators are available in many shapes and sizes, its rigid nature provides great mechanical strength. The porcelain used for bushings on high-voltage transformers can stand alone, without the use of other materials.

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