Calculation of Electric Fields of EHV/UHV Transmission Lines with Four Circuits on the Same Tower

After modeling a transmission line with double 1 000kV circuits and double 500kV circuits on the same tower,electric field intensity on the wire surface of the 4 EHV/UHV circuits and the filed at 1.5 mabove ground are calculated.By setting charges in the transmission lines with a charge simulation method,the current UHV double circuits drum power,single circuit cathead tower,single circuit glass tower,and single circuit compact tower are compared with this four circuit transmission lines.The results show that the electric field intensity on the transmission line surface of the circuits is no higher than the other towers.Meanwhile,the power frequen- cy electric field intensity on the ground is clearly less than the other towers.The theoretical basis is that 500kV wires on the same tower shield the majority of electric field in the ground direction of the 1000kV wires.