1. Increase the conveying capacity.

The natural power of 1000kV uhv transmission line is close to 5 million kilowatts, about five times that of 500kV transmission line.The uhv transmission capacity of + / -800kv can reach 6.4 gigawatts, 2.1 times that of + / -500kv and 1.7 times that of + / -620kv.

2. Increase the stability limit.

The electrical distance of a 1000kv line is equivalent to 1/4 ~ 1/5 of a 500kv line of the same length.In other words, under the same power transmission condition, the maximum power transmission distance of 1000kV uhv transmission line is about 4 times of 500kV line.The adoption of + / - 800kV dc transmission technology enables ultra-long distance transmission and economic transmission distance up to 2500km and above.

3. Reduce line consumption.

Under the condition that the total cross section and transmission capacity of the wire are the same, i.e., R and S values are equal, the resistance consumption of 1000kV ac line is 1/4 of 500kV ac line.Resistance consumption of + / - 800kV dc line is 39% of + / - 500kV dc line and 60% of + / - 620kV dc line.

4. Reduce project investment.

The comprehensive cost per unit transmission capacity of 1000kV ac transmission scheme is about three-quarters of that of 500kV transmission scheme.The combined cost per unit transmission capacity of + / - 800kV HVDC transmission scheme is also about three-quarters of that of + / - 500kV HVDC transmission scheme.

5. Save corridor area.

Ac uhv: the corridor width of double loop circuit and single loop circuit of cat head tower is 75 meters and 81 meters respectively, and the conveying capacity of unit corridor is 133,000 kw/m and 62 kw/m respectively, about three times of the same type of 500kV circuit.

The transmission capacity per unit corridor width is 84,000 kw/m, which is 1.29 times that of the schemes of 500kV and 3 kw, and 1.37 times that of the schemes of 620kV and 3.8 kw.

6. Improve the grid structure.

Long distance power transmission through uhv can reduce the demand for installing units in the load center area and thus reduce the short-circuit current amplitude.Long distance input of 10 gigawatts of power is equivalent to the reduction of 17 local installed units of 600 gigawatts.Each 600mw unit adds about 1.8ka to the short-circuit current of the 500kv system in the nearby area. If these units are installed in the load center area, the short-circuit current degree of the local power grid will be greatly affected.

Through the uhv power grid, the layered partition structure can be realized, and the system structure including uhv can be optimized to fundamentally deal with the problem of excessive short-circuit current.