What is Pole Mounted Substation? Use, Capacity, Diagram
A mounted Substation is an outdoor step-down distribution substation that is placed on an overhead pole. It is the cheapest, smallest, and simplest substation. This type of substation does not have any building works. The transformer is mounted on an H-type pole or Four Pole Structure. The electrical power supply comes into our house mostly from this pole-mounted substation.
Pole Mounted Substation Capacity
Voltage Rating: The voltage rating of the pole-mounted substation is 11KV/400V. It provides a line voltage of 400V for a three-phase system and 230V for a single-phase system.
Current Capacity: The current capacity of the pole-mounted substation varies with the load requirements. The current balancing system is arranged, so the transformer can give the maximum efficiency.
Power Capacity: The power capacity of the pole-mounted substation is up to 250 KVA.
Transformer Connection: The transformer in pole pole-mounted substation is generally delta-star connected.
Pole Mounted Substation Use
Pole mounted substation is used for the low-voltage power distribution. It generally supplies the electrical power supply to the domestic consumers. It steps up the voltage from three phase three wire 11KV into three phase four wire 400V and single phase 230V power supply. The main advantage of this substation is it provides output in both three-phase and single-phase. So it can be used to provide power supply to both the single phase and three phase consumer.
Structure and Construction of Pole Mounted Substation
All the equipment and transformer are placed on the pole. The 11 KV incoming lines are connected to the transformer through the gang isolator and HT fuses. A triple pole mechanically operated gang isolator switch is used. When the transformer needs to disconnect from the power supply the isolator can be operated from the downside handle.
Also, the lightning arrester is connected at the High voltage side which will protect the transformer and its output circuit from the lightning stroke. An Oil Circuit Breaker(O.C.B) is installed on the Low voltage side of the transformer that will disconnect the output load or consumer automatically when any fault occurs. During the maintenance or repair of the transformer, both of the high-voltage side isolator and low-voltage side circuit breaker should be turned off so the transformer will be completely disconnected or be isolated from the incoming power supply and consumers. The installation and maintenance cost of the pole-mounted substation is very low compared to other substations because it has low-capacity equipment and structure.
Diagram of Pole Mounted Substation
You can see, the 11KV lines are first connected to the fuse. It is a single-line diagram, which is why here only one fuse is shown in actual all the three phases have separate fuses. The output of the fuse is connected to the isolator. And the output of the isolator is connected to the transformer input terminal. The output of the transformer is connected to the Oil Circuit Breaker. And the output of the oil circuit breaker is provided to the consumer. Also, you can see the lightning arrester is connected with incoming lines.
Three-phase consumers are supplied from all the three phases so they will get 400V. The single-phase consumers are supplied with any one phase and neutral, so they will get 230V. Single-phase consumers are equally distributed from the transformer, so the transformer can give the maximum output with high efficiency.
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What is Pole Mounted Substation? Use, Capacity, Diagram
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December 24, 2021
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Reviewed by Author
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December 24, 2021
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