IMPROVEMENT OF DIRECT LIGHTNING STRIKES PERFORMANCE OF 110 kV OVERHEAD LINES BY MEANS OF THE CHARGE TRANSFER SYSTEM

Abstract

The outage rate of 110kV overhead lines is greatly affected by direct lightning strikes on the line. Many methods have been applied to improve the effectiveness of lightning protection for overhead lines such as using shield wires, surge arresters, reducing tower surge impedance and grounding impedance. This article introduces a protection method against direct lightning strikes for 110kV overhead lines using a Charge Transfer System (CTS). Numerical simulations using the finite elements method demonstrated that an increase ionization by the CTS leads to a decrease in electric field strength in the vicinity of the tower top. Therefore, the probability of a direct discharge from the cloud to the tower decreases. Experimental datas of the double circuit lines 172, 173E10.5 - 176, 175E1.35 within the CTS of Hanoi High Voltage Grid Company in 2022 do not show any failure due to lightning strikes on the lines.