Liquid Dielectrics and Solid Dielectrics - High Voltage Engineering

TL;DR

This content discusses the properties and applications of liquid and solid dielectrics used for insulation in electrical devices.

Transcript

hello friends today we are going to start with our next topic related to the subject high voltage engineering that is breakdown in liquid and solid dielectrics let us begin with the introduction to this liquid and solid dielectrics first let us understand what is liquid dielectrics see there are certain inherent properties due to which these two di... Read More

Key Insights

• 🫢 Liquid dielectrics are chosen for insulation purposes due to their ability to dissipate heat and cover a larger area compared to gases.
• 😘 The dielectric strength of liquid dielectrics is often lower than expected, but they still find widespread applications in various electrical devices.
• 🛢️ Transformer oil, synthetic hydrocarbons, halogenated hydrocarbons, and vegetable oils are examples of liquid dielectrics used in different applications.
• 💆 Solid dielectrics are used to insulate electrical circuits and devices, but they have the disadvantage of getting permanently damaged during breakdown.
• 🫗 Moisture, oxidation products, and other contaminants can significantly reduce the electrical strength of liquid dielectrics.
• 🥶 It is crucial to process liquid dielectrics to ensure they are free from moisture, oxidation, and other contaminants to maintain their insulating properties.
• 🚾 A small amount of water in transformer oil can significantly reduce its electrical strength.

Questions & Answers

Q: Why are liquid dielectrics preferred over solid and gaseous dielectrics?

Liquid dielectrics are selected for insulation purposes because they are denser than gases and can cover a larger area in the insulating material. They can also dissipate heat more efficiently through convection.

Q: What is the dielectric strength of liquid dielectrics?

The expected dielectric strength of liquid dielectrics is 10 mega volt per centimeter based on the Paschen slope law. However, in practice, it is often around 100 kilo volt per centimeter.

Q: What are the applications of liquid dielectrics?

Liquid dielectrics, such as transformer oil, synthetic hydrocarbons, halogenated hydrocarbons, and vegetable oils, can be used as impregnants in cables and capacitors, heat transfer elements in transformers, and as a medium to quench arcs in circuit breakers.

Q: What factors can reduce the electrical strength of liquid dielectrics?

The presence of moisture, oxidation products, and other contaminants in liquid dielectrics can reduce their electrical strength. Even a small amount of water, such as 0.01 percent in transformer oil, can reduce the electrical strength by 20 percent.

Summary & Key Takeaways

• Liquid dielectrics, like gases, are chosen as insulating mediums to prevent electrical shocks or current leakage. They are denser than gases and can effectively dissipate heat.

• Liquid dielectrics have a higher dielectric strength compared to gases but lower than the expected value. They are commonly used in cables, capacitors, transformers, and circuit breakers.

• Solid dielectrics are used to insulate different electrical circuits and devices. However, they have a higher breakdown strength compared to liquids and gases but get permanently damaged during breakdown.