13. UHV (1000kV) power transmission technologies
13.1 Background
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Fig. 13.1 shows the Japanese history of the electric power generation and Table 13.1 possible transmission power vs. voltage. The power demand is still increasing.

Applying the new technology of insulation coordination mentioned in the followings, the dimension of UHV transmission line tower can be only 130% of EHV(500kV) as shown in Fig.13.2.

In Table 13.1 some examples of transmission power limits by some voltages of lines are shown, where the assumptions are introduced.:
* For line reactances, positive sequence parameters of one circuit of lines are introduced.
** The possible transmission powers are calculated by the equation,:
where, E: Volt r.m.s phase to phase, X: Line reactance, and considering the dynamic stability condition, the coefficient 0.5 is introduced.
From these, especially considering the necessary ground area for the transmission lines, the demand for the UHV transmission is clear.

Table 13.1 Possible transmission power vs. voltage (150km line)
SHV SHV EHV EHV UHV
Nominal voltages 66kV 154kV 275kV 500kV 1000kV
Line consts.*
1 mH/km 1,3 1,3 0,96 0,86 0,80
X W/150km 61, 61, 45, 40, 38,
Max. transm. power MW** 36, 195, 840, 3.125, 13.158,

This page is based on Prof. E.Haginomori's lectures in Tokyo Institute of Technology, and edited by Japanese ATP User Group. Copyright (C) Eiichi Haginomori and Japanese ATP User Group.