In ring main distribution system, each distribution transformer is fed with ( ) feeder / feeders.

Explanation:

Ring Main Distribution System

Definition: A ring main distribution system is a type of electrical power distribution network where the distribution transformers are connected in a closed loop or ring. This configuration ensures that each transformer can be fed from two directions, enhancing the reliability and flexibility of the power supply.

Working Principle: In a ring main distribution system, the transformers and substations are interconnected in a ring. This setup allows the power to flow in multiple paths, ensuring that if one path is interrupted due to a fault or maintenance, the power can still reach the transformers from the other direction. Each distribution transformer in this system is typically fed with two feeders, providing redundancy and improving the reliability of the power supply.

Advantages:

• Enhanced reliability: If one feeder fails, the transformer can still be fed from the other feeder, minimizing power outages.
• Flexibility in maintenance: Maintenance work can be carried out on one section of the ring without interrupting the power supply to the consumers.
• Balanced load distribution: Power can be distributed more evenly across the network, reducing the chances of overloading any single feeder.

Disadvantages:

• Higher initial cost: The construction of a ring main distribution system requires more cable and equipment compared to a radial system, leading to higher initial costs.
• Complexity in design and operation: The closed loop structure requires careful planning and coordination to ensure proper load management and fault isolation.

Applications: Ring main distribution systems are commonly used in urban and industrial areas where high reliability and flexibility are essential. They are particularly suitable for networks with a high density of consumers and critical loads that require a continuous power supply.

Correct Option Analysis:

The correct option is:

Option 2: Two

This option correctly describes the functioning of a ring main distribution system. Each distribution transformer is fed with two feeders, providing redundancy and enhancing the reliability of the power supply. In the event of a fault or maintenance on one feeder, the other feeder can continue to supply power to the transformer, ensuring uninterrupted power delivery to the consumers.

Additional Information

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

Option 1: Four

This option is incorrect as it overstates the number of feeders typically used in a ring main distribution system. While having multiple feeders can enhance redundancy, four feeders per transformer are not commonly used due to the increased complexity and cost.

Option 3: Only one

This option is incorrect as it does not provide the redundancy and reliability that are the primary advantages of a ring main distribution system. Feeding each transformer with only one feeder would make the system more susceptible to faults and outages.

Option 4: Three

This option is also incorrect as it suggests an atypical number of feeders for a ring main distribution system. While having three feeders could provide some level of redundancy, it is not the standard practice and would add unnecessary complexity to the system.

Conclusion:

The ring main distribution system is designed to enhance the reliability and flexibility of the power supply by feeding each distribution transformer with two feeders. This setup ensures that power can be delivered from either direction, minimizing outages and allowing for easier maintenance. Understanding the correct configuration and its advantages is crucial for designing efficient and reliable power distribution networks.