What are Electrical insulators│Types of Insulators,Materials,Range│Electronicsinfos

What Are Electrical Insulators?

An electrical insulator is an equipment or component in which the insulator does not allow the electric current. Just imagine how important insulation is in our daily life?

Insulation protects humans from getting electrocuted. The wire carries electricity to your computer with an insulating material that protects you. Good insulators include glass, air, paper, rubber, and mica. in this article, we discuss different types of insulators that exist in a market which used in transmission and distribution. System insulation depends on the value of voltage.

 The purpose of the insulator is to provide support to the overhead line conductors and stop the current flow towards the earth. In this article, we will discuss types of insulators, different types of insulating materials, the relation between moisture And insulation, and how we protect electrical insulation against moisture.

General Properties of insulating material

• The dielectric strength of the insulating material must be high.
• The Material insulating resistance is high.
• The thermal expansion of the insulating Material must be low.
• The insulator Material must be non-ignitable.
• The thermal strength of the insulating material is high.
• The mechanical strength of the insulators is high
• Low permittivity

                                    

Types of Electrical Insulators

There are many types of insulators used in Electrical but in this article, we discuss the most common types of insulators that are used for transmission and distribution purposes which are described below

• pin type insulator
• post type insulator
• suspension insulator
• shackle insulator
• Hollow insulators
• porcelain insulators

Pin Type Insulators

The pin insulator has grooves on the top side to support the conductor. There are two sides of the groove: the first on the top side is in a straight line position and the second side groove is in an angle position. The voltage range of the pin insulator is up to 33 kV in the transmission and distribution system. The stacked plate shows the voltage level. For low voltage, we used a single plate and for high voltage, we used stacked plates to provide adequate insulation to overcome puncture under surge conditions

The mechanical strength of the insulator is high. pin type insulator is simple so requires less maintenance.

Materials:

• porcelain
• polymer
• ceramic
• silicon rubber

Range:

up to 33 kV system

post-type insulator

post-type insulators have a comparatively higher number of sheds as compared to pin-type insulators. post insulator is a high-voltage insulator. the design of post-insulators based on ANSI, IEEE and other standards. post insulators are manufactured with porcelain and other materials. The mechanical strength of post-type insulators is high. we used post-type insulators in distribution and transmission lines. the thermal stability of post-type insulators is high. post-type insulators used in the Substation system.

Types of post-type insulator w.r.t Design

• tie top-line posts
• horizontal clamp top-line posts
• horizontal (gain base) line posts
• brace post insulators
• vertical clamp top-line posts

Materials :

• plastic
• polyvinyl-chloride
• porcelain
• glass
• ceramic

Range:

11 kV to 765 kV

suspension insulator

There are two parts of a suspension insulator .one part is the insulator's arm and another part is the cross arm. suspension type insulator protects an over-headed transmission line. The voltage rating of this insulator is more than 11kv. This insulator is highly flexible because The string is free to swing in any direction. The suspension insulator is flexible so that easily be replaced with a new unit. we connect suspension-type insulators in series to enhance the power of the insulation

Materials:

porcelain material

Range

>11Kv

Shackle insulator

A shackle insulator is a low-voltage insulator that is used in distribution circuits. we also called the spool insulator. There are two positions of this insulator one is vertical and the other horizontal position. the can be easily designed. they are mechanically strong. we used the insulator with a bolt directly in the cross arm. directly. The shackle insulator is round-shaped and includes a hole in the middle side for bolting. the galvanized plate is used on both sides of the shackle insulator.

Materials:

porcelain material

Range:

>33Kv

Hollow insulators

The mechanical strength of hollow insulators is high. the shape of the hollow insulator is cylindrical, circular and conical. Hollow insulators are components of the bushings that provide safety to transformers and circuit breakers. in the instrument transformer like CT and PT, we also used hollow insulators to support the instrument transformer. hollow insulators are mechanically strong that's why we used this type of insulator to protect the circuits. hollow type insulators are used in different positions as described below

• Lightning arresters.
• Power transformer bushings
• CT(current transformer)
• PT(Potential transformers)
• Capacitive voltage transformers
• Circuit breakers

Materials:

porcelain material

Range:

33kv up to 800kv

porcelain insulators

The usage of Porcelain insulators is common in transmission and distribution systems. porcelain insulators are environmentally friendly. the electrical strength of the porcelain insulators is higher as compared to the other insulators .porecelain insulator surface degradation rate is low. Support for porcelain transport encasings isn't needed. The coating provides protection against soil and contamination.

                                                   

Range of Different Insulators

Factor to be considered during the selection of insulator

• thermal conductivity must below
• mechanically strength must be high
• environment friendly
• degradation level is low
• it must be fireproof
• the cost of the insulator is low
• It must be odourless
• it must be water repellent
• the weight of the insulator is light
• combustibility level is low
• thermal conductivity is low

Insulating Materials

• plastic
• mica
• wood
• glass
• porcelain
• glass
• steatite
• polymer
• artistic
• PVC

Conclusions:

In this article, we discuss different types of insulators which are widely used in the transmission and distribution system. we also discuss the material which is used in the manufacturing process of insulators.

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