Research On Traveling Wave Protection Strategy Of HVAC Transmission Line

In recent years,with the continuous progress of power grid technology,China's requirements for transmission lines continue to rise,and for the safe operation of long-distance,high-voltage power systems continue to rise.Finding fault location accurately and rapidly removing it has become one of the main subjects of current research.A traveling wave protection strategy based on two terminal electrical quantities is proposed for the related problems in traveling wave operation.This article mainly has done the following work and the research results are as follows.:(1)Introduce the basic theory and influence factors of traveling wave.This paper discusses the single-end and double-end traveling wave protection methods,discusses the attenuation and distortion of traveling wave in the process of operation,and studies the interference factors of traveling wave in signal acquisition.(2)A traveling wave differential protection strategy based on mathematical morphology is proposed in this paper.In this paper,the random noise and impulse noise in traveling wave signal are filtered by mathematical morphology,and then the fault traveling wave current signal is transformed by phase mode to obtain the forward and backward traveling wave signal.According to the extracted traveling wave signal and the discriminant formula,the fault types inside and outside the region are determined to achieve the purpose of traveling wave differential protection.(3)Aiming at the influencing factors of traveling wave fault location,a traveling wave distance protection strategy based on two-terminal electrical quantity method is proposed.Firstly,the fault type is determined according to the current and voltage amplitude of the two terminals and the fault point,and then the three-phase sequence voltage of the two terminals is extracted as the main parameter of the study.According to the unbalance of the three-phase sequence voltage,the corresponding voltage threshold is set to calculate the fault distance and analyze the three-phase distance protection action.It shows that this method is effective in ensuring the accuracy and reliability of protection.