What is the standard rating for three-phase distribution transformers for rural supply?

Explanation:

Three-Phase Distribution Transformers for Rural Supply

Definition: A three-phase distribution transformer is an electrical device that converts high-voltage electricity from the power grid to a lower voltage suitable for use in homes and businesses. These transformers are crucial in the distribution of electricity, especially in rural areas where the electrical infrastructure may be less robust compared to urban settings.

Purpose: The primary purpose of a three-phase distribution transformer in rural supply is to step down the high voltage from the transmission lines to a level that can be safely used by residential and commercial customers. This ensures efficient and reliable delivery of electrical power to rural communities.

Standard Ratings: The standard ratings for three-phase distribution transformers are determined based on the typical electrical load requirements in rural areas. These ratings ensure that the transformers can handle the expected load without overloading or causing voltage drops.

Correct Option Analysis:

The correct option is:

Option 2: 10 kVA, 16 kVA, 100 kVA, 200 kVA, 500 kVA

This option lists the standard ratings for three-phase distribution transformers commonly used in rural supply. These ratings are as follows:

• 10 kVA: Suitable for small rural households or agricultural applications with minimal electrical demand.
• 16 kVA: Appropriate for slightly larger households or small commercial establishments.
• 100 kVA: Ideal for medium-sized rural communities or larger agricultural operations.
• 200 kVA: Used for larger rural communities or small industrial applications.
• 500 kVA: Suitable for very large rural areas or significant industrial operations that require a substantial amount of electrical power.

These ratings ensure that the transformers can efficiently manage the electrical load in rural areas, providing stable and reliable power supply to various types of consumers.

Important Information

To further understand the analysis, let’s evaluate the other options:

Option 1: 6/8 kVA, 10/12 kVA, 16/20 kVA

This option lists lower ratings that are not typically used for three-phase distribution transformers in rural supply. The ratings 6/8 kVA and 10/12 kVA are more suitable for very small applications or individual households, but they do not cover the broader range of requirements seen in rural communities.

Option 3: 415 VA, 11000 VA, 33000 VA, 66000 VA, 132000 VA

This option lists ratings in volt-amperes (VA), which is not the standard unit for transformer ratings. Additionally, the values 11000 VA, 33000 VA, 66000 VA, and 132000 VA are more relevant to high voltage transmission systems rather than distribution transformers for rural supply.

Option 4: 11/0.433 kVA

This option seems to be a typographical error as 11/0.433 kVA does not make sense in the context of transformer ratings. The correct format should include a single kVA rating representing the transformer's capacity.

Conclusion:

Understanding the standard ratings for three-phase distribution transformers is essential for ensuring efficient and reliable power supply in rural areas. The correct option, which lists 10 kVA, 16 kVA, 100 kVA, 200 kVA, and 500 kVA, reflects the typical requirements for rural electrical distribution. These ratings provide a range of capacities suitable for various applications, from small households to large industrial operations, ensuring that the electrical infrastructure can meet the diverse needs of rural communities.