Spot network substations have the secondary network with all supply transformers bussed together on the secondary side at one location. Spot networks are considered the most reliable and most flexible arrangement of connecting power to all types of loads.Cugnet, Pierre: Master's Thesis - Power Distribution Systems Switching can be done without interrupting the power to the loads.

Spot network substations can be used to make the interconnected distribution networks to serve a single campus or facility. Examples of such single campuses and facilities include hospitals, major data processing centers (especially those using uninterruptible power supply), and sports arenas that regularly broadcast nationally televised events.

In large cities, many electric utility companies use interconnected distribution networks to serve the downtown core. The interconnected network has multiple connections to the points of supply.

Reverse current relays are used to detect and open circuits that are letting the electrical current flow back towards its source. A local spot network of 2, 3, or 4 substations can be installed to provide particular facility, like a large hospital or computer and major data processing center, with more reliable power. Any of the 4 substations can carry all of its connected loads. Some arrangements have one dedicated circuit that only serves the spot network substations in a single facility. The other spot network substations maybe connected to circuit(s) that also serves many other users.

Electricity distribution networks are typically of two types, radial or interconnected (see spot network substations). A radial network leaves the station and passes through the network area with no connection to any other supply. This is typical of long rural lines with isolated load areas. In general, the radial distribution network is has more power failures than the interconnected distribution networks.

References

External Links

• NIH NIH Design Policy and Guidelines

• NIH Single Line Diagram of 3 Primary Feeders and 1 Emergency Feeder, Page 513 of 713

• ComEd Distributed Resources on Spot Networks at ComEd