Design of an Electromagnetism-Based Transmission Line Galloping Test System

Abstract

Existing transmission line full-scale tests rely on natural winds and have low test efficiency. In this paper, taking a reduced-scale test line with a 35.4 m span as an example, an electromagnetism-based transmission line galloping test system is designed. The plunger electromagnet periodically provides mechanical energy which vibrates the wire system in place of complex pneumatic loads. The finite element model of the electromagnet device is established and the influence of related parameters is analyzed. The power supply and control circuit of the excitation device are designed. The vibration of the transmission line is monitored by accelerometers and the displacement calculation method based on discrete wavelet transform (DWT) is proposed. Considering the geometric nonlinearity of the wire system, an adaptive excitation method based on wavelet decomposition and reconstruction of the acceleration signal is proposed. The vibration response of the wire under different coil currents and excitation modes is monitored and analyzed. The results show that the actual line galloping can be simulated by the designed electromagnetic system, the vibration frequency is close to the second natural frequency and the vibration amplitude can be controlled by changing the coil current.