We’ve all been on wonderful walks through the British countryside, enjoying the fields, forests and canals around us. It’s hard not to notice the sound of the birds, the scents of the countryside and the beautiful scenery. Yet there is always one consistent feature that you’ll be hard-pressed to miss; the electricity pylon. These massive structures, which stretch out for miles over the horizon, have been a part of the British landscape for nearly 100 years. In fact, there are now over 90,000 pylons across the country, transporting high-voltage electricity through over 4,470 miles of overhead lines. Typically operating at 275kV and 400kV respectively, these lines play a crucial role in the delivery of electricity from remote power stations to cities, towns and villages across the country. What is high-voltage transmission and why is it advantageous to use it?
What is high-voltage transmission?
High-voltage transmission is the transportation of electricity over long-distances at voltages of up to 275,000 volts (275kV) and 400,000 volts (400kV) respectively. We transfer electricity at such high voltages out of necessity; this is to enable large quantities of power to be transported across long distances without incurring excessive power losses as a result of resistance in electrical conductors.
What are the advantages of high-voltage transmission?
Reduced Power Loss
The long transmission lines you see connecting the huge pylons are typically made from copper, aluminium/* aluminium alloys. Within each transmission line is a level of resistance that contributes to power loss; this is known as “copper loss” or “I2R loss”. The amount of power lost in a transmission line is usually relative to the amount of current flowing through it. Lower currents incur less power loss, therefore high-voltage levels are utilised to reduce current to effective levels. If the same amount of power was transmitted over a distance at a lower voltage (and higher current), there would be a greater loss of power.
Reduced costs
Transmitting electricity at lower voltages requires a conductor that is substantially larger in size than needed for the equivalent transmission at higher-voltages. This is to decrease the amount of voltage drop in the circuit, which occurs when the voltage at the end of a run of cable is lower than at the beginning. To combat this, increasing the conductors size lowers the overall resistance of the cable length.
Furthermore, transmitting high-voltage electricity at lower currents helps to reduce cost; this is because high currents require thicker cables, which in turn waste energy as heat. Therefore, the national grid can utilise thinner, lightweight cables that are more cost-effective to manufacture. Plus, transmission towers do not need to be designed, engineered and produced to support heavier wires, again incurring less cost.
Improved efficiency
It won’t come as any surprise that the reduction in power loss – combined with the associated reduced costs – helps to drive efficiency in transmission of power. This helps to reduce power costs and lower equipment expenditure, thus enabling savings that can be reinvested into improved infrastructure which continues to drive performance and efficiency. Therefore the cycle of investment starts again.
The future of high-voltage transmission
There are currently a number of exciting international projects involving high-voltage transmission. The world’s longest under-sea electricity cable, which runs 450 miles connecting Norway and the United Kingdom, has recently begun operations. The £1.86bn project is set to harness the UK’s wind energy resources and Norway’s extensive hydropower. It is set to increase to a maximum capacity of 1,400MW within a three-month timeframe.
Plans have also been announced for a multi-billion pound, 440-kilometre “underwater energy super-highway” from Scotland to England. This is set to commerce work in 2024.
Network Power Connections
The advantages of high-voltage transmission are clear which plays an integral role in our society 24/7. Network Power Connections are proud to play a leading role within this sector, supporting a diverse portfolio of clients across the UK. Whether you need high or low voltage network design services, overhead line maintenance and construction or substation design, installation and maintenance, our specialists are well-equipped to assist.
If you’re looking for a reliable, trusted Independent Connection Provider with a wealth of expertise in high-quality, electrical supply solutions, contact us today on [email protected] or give us a call on 01905 611011 for a no obligation discussion!
