Field testing and data analysis of impact impedance of transmission line tower composed of weathering angle steel

Abstract

Weathering steel material has good corrosion resistance and mechanical properties. Compared with galvanized steel tower, weathering steel has longer operation life and lower operation and maintenance cost. With the pilot operation of weather resistant angle steel tower on the transmission line, its electrical performance has been widely concerned. The impact impedance of the tower is an important parameter to evaluate the lightning strike back performance of the tower. The rust layer formed on the surface of the weathering steel material will cause large lap resistance, which may increase the lightning strike back risk of the tower. In this paper, the impulse impedance test of a 220kV weathering angle steel tower in Fuyang, Anhui Province of China is carried out, and the circuit calculation of the test results is carried out to verify the rationality of the test data. The results show that: the zero frequency resistance of 220kV weathering angle steel tower is 1.027Ω, and the low frequency inductance is 311.94μH. The impact impedance results of the tower not only depend on the size, material and model of the tower, but also related to the impact waveform; the test results are in good agreement with the circuit simulation results.