High voltage direct current (HVDC) power systems use D.C. for transmission of majority power over long distances. HVDC lines are fewer costly, and fatalities are less related to AC transmission for long-distance power transmission. It connects the networks that have diverse rates and features.
High voltage is working for electrical power transmission to scale back the energy lost within the resistance of the wires. Doubling the voltage would bring an equal power at only half the present for a given quantity of power transmitted. Meanwhile, the facility lost as heat within the wires is directly proportional to the square of the present, doubling the voltage decreases the road losses by an element of 4. Even though power lost in transmission also may be reduced by increasing the conductor size, larger conductors are heavier and costlier.
High voltage may not willingly be used for lighting or motors. Therefore, transmission-level voltages must be reduced for end-use equipment. Transformers are wont to change the voltage levels in AC (AC) transmission circuits. Transformers prepared voltage changes practical. The AC generators were well-organized than those using DC. This looks that HVDC lines are more capable than AC lines by seeing all the advantages of DC. Then, the initial cost of the HVDC substation is very high. Their substation apparatus is quite complicated. Therefore, for long-distance transmission, it is better than power is generated in AC. But, it is changed into DC and then again converted back into AC for final use for transmission. This system is economical and also recovers the effectiveness of the system
How does the HVDC transmission system work?
By using a rectifier the A/C power may be converted into DC in generating substation. At both, the ends of a line in the HVDC substation or converter substation rectifiers and inverters are placed. The rectifier terminal changes the AC to DC, whereas the inverter terminal converts DC to AC.
The DC is flowing with the overhead lines and at the user end again DC is converted into AC by using inverters, which are located in the converter substation. The power rests the same at the sending and receiving ends of the line. DC is transmitted over long distances because it drops the losses and develops competence.
One system which has other than two converter stations and one transmission line is called a ‘point-to-point system’. It also is said a ‘two-terminal DC system’. Likewise, if a substation has extra than two converter stations and connects DC terminal lines, it is called a multiterminal DC substation.
Industry 4.0: World’s Longest Power Transmission Line
The 2,500 KM transmission line in Brazil is an 800 kV HVDC line that transmits electricity from the Belo Monte hydroelectric dam power plant to Rio de Janeiro, Brazil.
The overhead transmission line, which has transmission towers height of 105 meters & taller, crosses 80 cities along its route from the Amazon forest to Brazil’s southeast coast. It came into operation in September 2017. The line has two power booster stations at a gap of 1,000 KM each and is capable of transmitting 4,000 MW of electrical power.
Line losses are under 1 % – if this was done on AC power mode ~ line losses could be 25 % in this distance of 2,500 KM.