Experimental Study On Amplitude Death Mechanism Of The Dynamic System Of Transmission Line

China has a vast territory,and the terrain is high in the west and low in the east.It is distributed in a step-like manner.For the transmission of long-distance electric energy,it can only be carried out in the form of a large span.In recent years,with the global warming,severe weather such as winds,heavy rains,ice and snow have occurred frequently.Overhead transmission lines are large-span flexible structures,which is prone to low-frequency large-scale dancing under extreme environmental excitation,which is extremely unfavorable for the line operation.The damping effect of traditional methods such as damper,detuning pendulum and spacer bar is not obvious.In this paper,a vibration attenuation control method based on amplitude death mechanism is proposed.Based on a 220 KV transmission line project in Hunan Province,a three-tower two-span three-phase transmission line test model,a variable stiffness phase-to-phase coupler and a time delay excitation system were designed and fabricated based on the principle of dynamic similarity.The coupling strength,delay coupling and frequency were considered comprehensively.An experimental study on the amplitude death mechanism of in-plane and out-of-plane directions was carried out.The specific work is as follows:1.Based on the principle of dynamic similarity,a three-tower two-span three-phase transmission line test model,a variable stiffness phase-to-phase coupler and a time delay loading device were designed and fabricated.The rationality of the test model is verified by linear analysis,modal analysis and synchronic analysis.The unfavorable working conditions of large vibration in-plane and out-of-plane directions of the line are determined by dynamic response test analysis.2.Considering the time delay coupling,the coupled vibration-damping test of three phase transmission line is studied.Based on the similarity principle,the excitation delay time range of the dancing wind speed segment is obtained.By testing and analyzing the dynamic response of the three-phase transmission line under different time delay excitations,the delay parameters of the amplitude death mechanism of the transmission line dynamic system are studied.The delay parameter interval of the system amplitude death is obtained.3.Considering the frequency-mismatched,the coupled vibration-damping test of three phase transmission line is studied.Firstly,the relationship between the tension of the transmission line and the frequency is analyzed.On this basis,the tension of the line is adjusted to realize the frequency mismatch of the three-phase line.The power line is tested and analyzed by the power response of the transmission line under different frequency mismatches.The mismatch frequency parameters of the system amplitude death mechanism are studied,and The law of the amplitude death characteristics of the system with the mismatch frequency parameters is obtained.4.Considering the coupling strength,the coupled vibration-damping test of three phase transmission line is studied.Consider the.The phase-coupler adopts the triangular topology configuration.Through the test and analysis of the dynamic response of the three-phase transmission line under the different phase-coupler stiffness,the coupling strength parameters of the amplitude-death mechanism of the transmission line dynamic system are studied.The range of coupling strength parameters for the amplitude death of the system at partial excitation frequencies is obtained.