The document discusses breakdown mechanisms in solid dielectric materials. Solid materials have higher breakdown strength than gases and liquids. When breakdown occurs in solids, the material is permanently damaged and cannot recover its original breakdown strength. The principal breakdown mechanisms for solids are intrinsic or ionic breakdown, electromechanical breakdown, thermal breakdown, electrochemical breakdown, and treeing and tracking. The breakdown mechanism depends on factors like temperature, impurities, and the time of voltage application.

1. HIGH VOLTAGE
ENGINEERING
 TYPES OF
BREAKDOWN
MECHANISMIN SIMPLE
LAUNGUAGE
LEC # 16
BREAKDOWN
IN SOLIDS

2. BREAKDOWN OF SOLID
DIELECTRIC MATERIALS

3. BREAKDOWN MECHANISMS OF SOLID DIELECTRICS
Function of any dielectric materials is to isolate one current carrying
circuit from other circuit.
 Solid materials have higher breakdown strength than gaseous and liquids.

4. BREAKDOWN MECHANISMS OF SOLID DIELECTRICS
 Facts and Factors:
When breakdown occurred in solid, it is permanently damaged. Damaged
Solid materials can not recover their original breakdown strength.
Good Solids Dielectric Must Have:
 High Breakdown Strength
 Low dielectric loss
 High mechanical Strength
 Should be free from moisture

5. BREAKDOWN MECHANISMS OF SOLID DIELECTRICS
Factor Affecting the breakdown of Solids:
 Ambient Temperature.
 Mechanical Strength
 Impurities, Gaseous inclusion, water and moistures.
 Chemical deterioration.
 Permittivity.

6. BREAKDOWN MECHANISMS OF SOLID DIELECTRICS
The principal mechanisms for breakdown of Solid materials:
 Intrinsic Breakdown or ionic Breakdown
 Electromechanical Breakdown.
Thermal Breakdown
Electrochemical Breakdown
Treeing and tracking mechanism

7. BREAKDOWN MECHANISMS OF SOLID DIELECTRICS
 The mechanism of breakdown is a
complex phenomena in the case of
solids, and varies depending on the
time of application of voltage.
 Time of application plays an
important role in breakdown
process, for discussion purposes, it
is convenient to divide the time
scale of voltage application into
regions in which different
mechanisms operate.
Variation of breakdown strength with time after
application of voltage