Research On Fault Location Technology Of Three-terminal Wiring Transmission Line

With the continuous expansion of the scale of power grids,in order to save the investment cost of equipment and line corridors,three-terminal wiring transmission lines gradually become the main wiring of transmission lines.So how to achieve the accurate determination of the three-terminal transmission line fault location is a key point for safe operation of the grid.From a large number of practical operating experiences,the current three-terminal wiring are three-terminal power supply and one end for the pure load and two end for power supply three-terminal wiring.Aiming these two structures,this paper identifies fault branch first,then analyzes the fault location on the fault branch through theoretical analysis and simulation technology.Based on the concept of the positive sequence fault component,the phase relation of the fault component current in the T point of the three-terminal wiring is analyzed.The conclusion is that the phase of the fault component current is basically the same if it is an external fault.The phase of the fault component current is basically the opposite if it is an internal fault.Aiming at the three-terminal T-type transmission line,equivalent circuit model of fault component is established,and the phase and amplitude characteristics of the related fault component current when fault occurred on different branches are analyzed.Then the recognition method of fault branch which is suitable for the T type wiring.With the help of the MATLAB/Simulink simulation software,under different power transmission directions,the discriminative approach of the fault branch simulation procedure is delivered.Aiming at the three-terminal transmission line with pure load at one end,the amplitude and phase of the current in each branch is analyzed when fault occurs in different branches respectively.The characteristics of the positive change and the reverse change of the fault current are concluded.And the discriminative approach to determine the fault branch is delivered.The conclusion is then verified by simulation under different power transmission conditions.When the fault branch is determined,the refraction and reflection rule of the travelling wave in three-terminal T-type transmission line is delivered.And the methods to determine the fault point are provided,then the rule is verified with the help of simulation software.The fault branch is determined by analyzing the fault component current,and the fault location is determined by analyzing the travelling wave.According to this method,fault monitoring equipment is designed which meet the requirement by the three-terminal wiring.Meanwhile,the components and software and hardware configuration of this equipment is introduced,and the installation method of this equipment is given as well.