Discussion on electromagnetic environment of 1000 kV AC overhead transmission lines in China

Typical proposed 1000 kV single circuit of cup-shaped and compact tower, double-circuit on the same tower AC transmission lines electromagnetic environment problems were analyzed in this paper. Successive images method was applied to calculate conductor surface voltage gradient and power frequency electric field intensity (EFI) at the level of 1 m above ground surface. Corona loss (CL), radio interference (RI) and audible noise (AN) were calculated and the values of typical altitude above sea level were given and discussed. Calculation and discussion results show that three typical tower lines can satisfy electromagnetic environment control criteria by selecting suitable line parameters. Although there is no measured data in this paper, this can be a reference to the former research work of China UHV AC transmission line design. More suitable CL, RI, AN predicting methods and control criteria in China are needed to be discussed and determined by considering the future demonstration line operating experience and live line measured data, as well as the testing results of UHV AC test base station.