Overhead Transmission Line-Open Fault Detection In Urumqi 10kV Distribution Network

China's 10kV distribution systems are almost grounded via the arc-suppression coil or not grounded systems. Single-phase line-open without earth fault has been ignored for so many years because its damage is not so serious and the fault hasn't explained clearly so far.There is great change of negative current component when it happens the line-open fault.It is marked as the occurrence of the fault.And it can be concluded the phase characteristic of negative current in the line.In the transient course,there are plenty of harmonics in the fault line.Through the transient analysis,it is drawed that the amplitude of each harmonic in fault phase is greater than other phases.Harmonic current in fault line is far greater than other normal lines.In order to improve fault's disposal,the band-pass filter is used to filter the datum to get useful information.Then the absolute value integral method is used to acquire and amplify the differences of the components.Fault location is an importrant function in distribuiton automation.In the thesis,the transferred information from feeder terminal unit is computed with load's trapezoid fuzzy figure.The fault location is affirmed by the result of computation using the trapezoid fuzzy math theory.The ATP and Matlab softwares are used to simulate the 10kV lines in Urmuqi distribution network.And the results shows the reliability and accuration of the method in the thesis.