Homework SourseHow is the reliability concern for radial type and network t
Solution
An electric power distribution system is the final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers. Distribution substations connect to the transmission system and lower the transmission voltage to medium voltage ranging between 2 kV and 35 kV with the use of transformers. Primary distribution lines carry this medium voltage power to distribution transformers located near the customer\'s premises. Distribution transformers again lower the voltage to the utilization voltage of household appliances and typically feed several customers through secondary distribution lines at this voltage. Commercial and residential customers are connected to the secondary distribution lines through service drops. Customers demanding a much larger amount of power may be connected directly to the primary distribution level or the sub-transmission level.
Distribution networks are divided into two types, radial or network.
The cheapest and simplest topology for a distribution or transmission grid is a radial structure.
A radial system is arranged like a tree where each customer has one source of supply.Radial systems are commonly used in rural or suburban areas.Radial systems usually include emergency connections where the system can be reconfigured in case of problems, such as a fault or required replacement. This can be done by opening and closing switches. It may be acceptable to close a loop for a short time.
This tree-like structure grows outward from the substation, but for reliability reasons, usually contains at least one unused backup connection to a nearby substation. This connection can be enabled in case of an emergency, so that a portion of a substation\'s service territory can be alternatively fed by another substation.
A network system has multiple sources of supply operating in parallel. Spot networks are used for concentrated loads.
