View
224
Download
0
Category
Preview:
Citation preview
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
1/15
Properties And Behavior Of
Composite & SolidInsulating Materials
By
Sachin Bhandari (EE03-64)
Tanmay Adke (EE03-67)
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
2/15
Classifications Of Insulators
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
3/15
Classes of Insulation
Following are the different classes ofinsulation
Y class (up to 90o C)
A class(up to 105o
C) E class (up to 120o C)
B class (up to 130o C)
F class (up to 155o
C) H class (up to 180o C)
C class (above 180o C)
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
4/15
Solid Insulators
Following are the solid insulators
Glass Insulator Egg shapedstrain insulators
Ceramic
insulator
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
5/15
Composite Insulators
Two commonly used elastomericmaterials are silicon rubber & EDPM(Ethylene propylene diene monomer)rubber
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
6/15
A continuous strand of glass fiber is wetted in a controlled manner
in a liquid resin bath, and then wound between and aroundbushings.
The shield layer and weather sheds, both made of a polymer are
then injection molded over the body.
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
7/15
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
8/15
Characteristics of Insulating Materials
Good insulating materials shall have thefollowing characteristics Good mechanical strength. Good heat conductivity.
Non-hygroscopic Must have the ability to withstand theallowable temperature without any changein the physical and chemical properties.
Composite insulators are less costly, lighterin weight, and have excellent hydrophobiccapability.
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
9/15
Behavior of solid insulating materials
The highest breakdown strengthobtained under carefully controlledconditions is known as the "intrinsic
strength" of the dielectric.
Dielectrics usually fail at stresses
well below the intrinsic strength dueusually to one of the following
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
10/15
Causes
electro-mechanical breakdown
breakdown due to internal
discharges surface breakdown (tracking and
erosion)
thermal breakdown electro-chemical breakdown
chemical deterioration
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
11/15
Behaviour Of Different Insulating Materials
Fig. The switching impulse voltage is generated with a marxgenerator.
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
12/15
Electro-mechanical breakdown
When an electric field is applied to adielectric between two electrodes, amechanical force will be exerted on thedielectric due to the force of attraction
between the surface charges. Thiscompression decreases the dielectricthickness thus increasing the effectivestress.
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
13/15
Breakdown due to internal discharges
the electric field strength in the voids is
higher than that across the dielectric. Thuseven under normal working voltages, thefield in the voids may exceed theirbreakdown value and breakdown may
occur.
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
14/15
8/3/2019 Properties and Behavior of Composite Solid Insulating Materials
15/15
Applications:
In over head Transmission lines Power Transformers
Rotating Machines
Circuit Breakers Cables
Power Capacitors
Electronic Equipments
Recommended