High Voltage Switchgear | An Introductory Guide | TheElectricalGuy

Summary

This video explores the three main types of high-voltage switchgear: Air Insulated Switchgear (AIS), Gas Insulated Switchgear (GIS), and Hybrid Switchgear. It explains how AIS uses air as an insulating medium, GIS uses SF6 gas for more compact designs, and Hybrid Switchgear combines features of both. The video covers the voltage ratings, typical applications, and advantages of each type, such as AIS being cost-effective and widely used, GIS being ideal for space-constrained areas, and Hybrid offering a balance of cost and space. Viewers will learn about the differences and applications in power systems.

Takeaways

• 😀 High voltage switch gear is one of three main categories of electrical switch gear, alongside medium voltage and low voltage switch gear.
• 😀 The video focuses on high voltage switch gear, explaining its role in power systems and their different applications in primary and secondary transmission.
• 😀 In India, high voltage switch gears are used for voltages above 52 KV, with common ratings of 72.5 KV, 145 KV, 245 KV, 420 KV, and up to 800 KV.
• 😀 High voltage switch gears are broadly classified into three main types: Air Insulated Switch Gear (AIS), Gas Insulated Switch Gear (GIS), and Hybrid/Mixed Technology.
• 😀 AIS uses air as an insulating medium between the phases, making it the most commonly used type of switch gear, with applications in outdoor substations.
• 😀 AIS switch gears are widely used in substations globally, covering voltage levels from 72.5 KV to 800 KV, with a current rating up to 4,000 amperes.
• 😀 For high voltage AIS switch gears, the insulation distance between phases increases with voltage ratings to ensure proper dielectric strength, often leading to the need for larger outdoor spaces.
• 😀 GIS uses SF6 gas as an insulating medium between phases, offering compact designs and improved dielectric properties compared to air, which helps save space in high voltage substations.
• 😀 GIS systems are factory-assembled and typically used indoors, ideal for locations with limited space or high land costs, though their initial investment is significantly higher than AIS.
• 😀 Mixed or Hybrid Technology switch gears combine elements from AIS and GIS, offering a balance between space requirements and cost, but are less commonly used than AIS and GIS.
• 😀 The video concludes by highlighting the importance of subscribing to the channel for further learning on related topics like medium voltage switch gear and other electrical engineering concepts.

Q & A

What are the three main types of electrical switchgear?

The three main types of electrical switchgear are high voltage switchgear, medium voltage switchgear, and low voltage switchgear.

Why is the video focused on high voltage switchgear?

The video is focused on high voltage switchgear because it is discussing its role in the power system, particularly in primary and secondary transmission stages, which require high voltage switchgear.

What is the typical voltage range for high voltage switchgear in India?

In India, the typical voltage ratings for high voltage switchgear are 72.5 KV, 145 KV, 245 KV, 420 KV, and up to 800 KV.

What is the dielectric insulation used in Air Insulated Switchgear (AIS)?

In Air Insulated Switchgear (AIS), air is used as the dielectric insulation medium between phases. The insulation between the phases is provided by air, which has a relatively weaker dielectric strength compared to other mediums.

How does the voltage level affect the spacing in AIS?

The voltage level directly affects the required distance between the phases in AIS. As the voltage increases, the spacing between phases must also increase to maintain adequate dielectric strength. For example, higher voltage ratings like 245 KV, 420 KV, or 800 KV require greater spacing.

What is the main advantage of Air Insulated Switchgear (AIS)?

The main advantage of AIS is its cost-effectiveness and widespread use. It is the most commonly used type of switchgear due to its relatively lower cost compared to other technologies like Gas Insulated Switchgear (GIS).

What insulating medium is used in Gas Insulated Switchgear (GIS)?

In Gas Insulated Switchgear (GIS), SF6 (sulfur hexafluoride) gas is used as the insulating medium between the phases, offering better dielectric properties compared to air.

What is the major difference between AIS and GIS switchgear?

The main difference is the insulating medium used. AIS uses air as the insulation, while GIS uses SF6 gas. GIS offers a more compact design due to its superior dielectric properties, but it is typically more expensive and is mostly used in indoor settings where space is limited.

Can different components be sourced from different manufacturers in AIS switchgear?

Yes, in AIS switchgear, components like circuit breakers, disconnectors, current transformers, and voltage transformers can be procured from different manufacturers and assembled together at the substation.

What is a Hybrid or Mixed Technology switchgear?

Hybrid or Mixed Technology switchgear combines elements of both AIS and GIS. Some components may use AIS technology (like disconnectors), while others use GIS technology (like circuit breakers), providing a balance between cost and space requirements.

What is the primary disadvantage of Gas Insulated Switchgear (GIS)?

The primary disadvantage of GIS is its high initial cost, which makes it less affordable compared to AIS, despite its more compact design and better dielectric performance. It is typically used in locations with high land costs or space constraints.

What is the typical application for AIS switchgear?

AIS switchgear is typically used in outdoor substations due to its need for more space. It is suitable for applications where land cost is not a significant concern and is the most widely used technology in power systems worldwide.