Substations
Energy networks use high pressure mains to efficiently supply large volumes over long distances. In Electricity distribution the pressure is termed as voltage. From controlling the voltage during distribution of energy to protecting the grid from long and widespread power cuts, substations are an integral part of the supply line. Comprised of multiple elements that allow distribution network operators (DNOs) to control, monitor and correct faults with the energy supply, the sophisticated design of substations safeguards the consistent flow of electricity in our homes and commercial buildings.
In this article, we will explain how a power substation works, discussing the process of magnetic induction and exploring the function of substations at different stages along the supply line.
What is a substation and its function?
Substations are facilities within an electricity distribution network that primarily increase and decrease the voltage of electricity as it travels from one part of the network to another. As power stations produce electricity at an incredibly high voltage, substations provide an efficient and safe way for DNOs to transform it to an appropriate voltage for the industries, businesses and homes receiving it.
How do substations work?
When a substation receives electricity from a power station, the voltage is increased or decreased by pieces of plant known as transformers before being distributed to other parts of the network. By placing substations strategically along their supply lines, DNOs can supply electricity at higher and lower voltages to meet the requirements of residential, commercial and industrial customers whilst keeping energy losses to a minimum.
While the transformers are crucial to the function of a substation, these facilities also contain circuit breakers and other safety equipment designed to predict network faults that could disrupt the electrical supply. Many of these components allow engineers to isolate faults in the system while continuing to supply energy to most of the network, minimising the number of customers impacted by the repair work.
What is inside a substation?
From the connection points between each component to devices designed to protect other components in the event of power surges, there are numerous elements inside a substation that enable it to distribute electricity more accurately and consistently. The most important parts of a substation include:
- Transformer: This electromagnetic machine is used to increase and decrease the voltage of an alternating current (AC) without changing the frequency or power. Made from alternating primary and secondary coils of wire, transformers transfer electricity from one coil to the other through a process known as magnetic induction.
- Circuit breaker: These are mechanical switches that interrupt the flow of electricity when they detect a fault, such as an overload or short circuit.
- High Voltage Switches: These manually operated switches allow engineers to isolate faults impacting the function of the substation.
- Recloser: This electromechanical device halts the current when it detects an excess of electricity or a fault and recloses to restore supply to customers if the fault has cleared.
Types of substations
There are numerous types of substations designed to perform specific functions across the network, which can be broadly categorised as either transmission or distribution substations. The most common types of substations include:
Step-Up Substations
The function of these transmission substations is to increase the voltage of electricity as it leaves a power plant, ensuring that it can efficiently travel through transmission lines without losing much energy.
Step-Down Substations
These transmission substations are connected to transmission lines and are designed to lower the voltage of the electrical current before it is distributed to different parts of the network.
Switching Substations
The final type of transmission substation manages the connections between sections of the network, without altering the voltage of the current. The main function of these substations is to isolate faults along a supply line, while maintaining a consistent energy supply to the rest of the network.
Distribution Substations
These substations reduce the voltage of the electrical current to a level suitable for use in homes and businesses.
Why are substations important?
At National Grid, we understand how crucial substations are to the present and future of electricity distribution. Over 197,000 of our substations currently supply electricity to homes and businesses throughout the Midlands, South West and South Wales, as well as providing the infrastructure to provide power to any housing developments or industrial projects the future might bring.
For more information about how substations factor into our plans for long-term development, or for clarity on what a substation is and its function within your local network, please get in touch or submit your query to our email address, info@nationalgrid.co.uk.
How does a substation work?
Long distance distribution whether Electricity, Gas, Oil or water is done at high pressure. A Distribution Electricity Substation primarily works by taking in high tension (High Voltage) electricity and transforming it to a much safer low voltage before arriving at houses or businesses.
But how does it work?
Electricity and magnetism go hand in hand. Moving electricity produces magnetism and a moving magnet produces electricity. The high voltage electricity is converted to magnetism inside a transformer by a big coil of wire and the magnetism is converted back into low voltage electricity by a smaller coil of wire.
What else is inside a substation?
Looking through the door of a typical substation you would normally see some high voltage switches, a transformer and a low voltage distribution board.
High voltage switches allow us to move the direction of flow of electricity to keep current flowing to other substations during works or to quickly change it if a fault occurs and get power back to our customers.
Transformers normally convert the voltage of the electricity from high to low.
Low voltage distribution boards are larger versions of a household fuse board. The fuse board feeds the electricity cables that carry the electricity to houses and businesses. The fuses are for isolation or to cut off the flow of electricity if a problem occurs on one of the circuits keeping the electricity flowing in the other circuits.
Circuit breakers are mechanical switches that interrupt the flow of electricity when they detect a fault, such as an overload or short circuit.
Automation equipment describes many of our switches are operated and monitored remotely to speed up switching to restore power quicker in the event of a fault on the network.
Automatic reclosing circuit breakers are devices protect circuits that are prone to intermittent faults. When a faults occur they disconnect power and after a set time automatically reclose in an attempt to restore power to our customers.
Remote monitoring equipment is when range of data is collected and fed back remotely to help indicate the position of faults or identify circuits needing attention.