Online Monitoring of Wind-Induced Vibration of Transmission Steel High Tower

Abstract

For transmission steel high tower, wind-induced vibration is significantly increased because of its high height and flexibility. Long-term vibration may damage tower and conductor. Thus, it is necessary to enhance ability of supervision the vibration and take measures to control it to allowable extent. In the paper, a method to achieve wind-induced vibration characteristics of high tower is studied using technologies of environmental incentive of wind load and wireless sensor acquisition and transmission signals. Monitoring device and sensor are designed to acquire meteorological environment parameters and tower vibratory responses. Parameters of tower vibration are analyzed and determined based on a monitoring system. The technologies are used for monitoring the wind-induced vibration of a large-span steel tubular high tower. It is demonstrated that the technologies put forward are practicable and suitable for field working condition, and present good effects. Keywords-transmission line; wind-induced vibration of tower; online monitoring I. INTRODUCTION New technologies like UHV, multi-circuit lines on the same tower, heavy section and bundled conductor are applied in transmission grid in China. Due to increase of structure height and flexibility of tower as well as effect of conductor's wind load, wind-induced vibration effect is significantly increased. Vibration may lead to fatigue damage of member and looseness of bolted connection even collapse of tower and effect vibration-proof of conductor. It is necessary to enhance supervision on wind-induced vibration of tower and take measures to control vibration to allowable extent so as to reduce adverse impact from wind-induced vibration. Although it is possible to acquire dynamic property and wind-induced response of the tower by theoretical calculation (1-5), vibration test is of important value. Since structure of actual tower is complicated, simplified model is applied in the analysis and calculation. By using result of actual measure on site, it is possible to verify theoretical algorithm, modify and perfect simplified model. In addition, in recent years, damage to transmission line from natural disasters like wind, ice and earthquake is increasingly severe. Test on dynamic property of tower under perfect condition may provide fundamental data or diagnosis on structural health and life evaluation during natural disaster or after use of a few years. At present, method common in vibration test is wire transmission, that is, sensor in each test point picks up vibration signal, which is then transmitted to signal collecting device for analysis and processing through signal shielded wire (6). However, field power of line may fail to guarantee supply thus impact normal use of some instruments. Layout of sensors and wiring is of high difficulty for high tower. SNR is low in long signal wire. In consideration of these, when applying conventional test method to high tower, it is necessary to resolve issues including transmission mode of vibration signal and analysis processing. Aimed at issues in wind-induced vibration test, the study adopts a new technology to test and analyze wind-induced response of transmission steel high tower by wirelessly transmitting vibration signal, under environmental incentive of wind load.