Power could now be transferred over longer distances using AC, by stepping up the voltage level for transmission and stepping down again for utilization. But, the developments in power electronics made us reconsider the DC power for transmission purposes. The AC vs. DC question has been around since the era of the war of currents.
Improvements in DC system A major problem that Edison could not solve was how to increase the transmission voltage of DC for transmitting the power over longer distances. With the development of mercury arc valves, it became easier to convert the power between AC and DC. The AC power could now be converted into DC after stepping up the voltage using a transformer and, at the end of the transmission line , it could be converted back into AC for stepping down.
Power capacitors are used to smooth voltage in the converter stations, as shown on the center of this image. HVDC is an energy infrastructure technology designed for the transmission of electricity from power plants at high voltages of to kV using direct current DC rather than alternating current AC.
The market for HVDC systems is expected to grow strongly in the next five years. Some of this growth is from the increased demand for electric power for electric vehicles and data centers. Still, most of the growth is from the need to transmit renewable energy from remote large wind farms and solar power plants that are often located long distances from those who consume the power they produce.
However, significant amounts of energy are lost when power is transmitted across long distances. To combat this, transmission system operators worldwide are increasingly adopting voltage-source converter VSC HVDC transmission systems, which help to minimize losses during power transmission.
Transmission losses often happen when some electrical energy is lost due to the resistance of transmission lines during transmission to residential and commercial buildings. Some losses also occur in the converter stations that convert energy generated by power plants. HVDC systems require transmission links that offer much lower losses than conventional AC transmission technologies.
However, engineers are still facing one monstrous issue with HVDC transmission: voltage stability. Consequently, long-distance transmission of electrical energy from remote facilities via submarine cables and long-distance land links is more efficient with VSC HVDC.
The transmission technology in VSC HVDC systems is particularly ideal for remote renewable energy power stations, including offshore wind farms, because converter stations can be designed to be compact enough to fit on an offshore platform.
Power flows are dictated by the relative impedance of various parallel paths from a given source of generation to a given load. HVDC, on the other hand, offers very fast and accurate control of the power flowing within its system. The operator can select the amount of power to be transmitted over the link. If that power is available at the sending end, it is then converted to DC, transmitted to the receiving end, converted back to AC and injected into the receiving AC system.
HVDC systems offer higher transmission capability and lower transmission losses over long distances than AC and provide better ability to control power flows. Additionally, they provide the ability to transmit more power over longer lengths of cables, making them an attractive alternative for the transition to renewable energy sources. Learn more about HVDC converter technologies, system components and the benefits for utilities.
Related Posts October 27, Construction. October 22, Power. The lower the current, the lower the resistance losses in the conductors. And when resistance losses are low, energy losses are low also.
High voltage transmission lines deliver electricity over long distances. The high voltage is required to reduce the amount of energy lost during the distance. If demand exceeds supply, a blackout occurs. Power can be generated at high voltages as there is no commutation problem. Ac voltages can be conveniently stepped up or stepped down. High voltage transmission of ac power reduces losses.
High voltage Transmission Advantages and disadvantages With increase in the transmission voltage size of the conductors is reduced Cross section of the conductors reduce as current required to carry reduces.
As the reduction in current carrying requirement losses reduces results in better efficiency. High voltages are used in transmission systems because a higher voltage implies a lower current for a given power of transmission. With a lower current, less heat is generated in the transmission lines and so less energy is wasted. Furthermore, it has excellent environmental benefits.
Therefore, a DC line requires less insulation.
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