FIELD: measurement equipment.
SUBSTANCE: invention relates to electrical measuring instruments and can be used for determination of a damage place in air and cable lines of power transmission in networks with an insulated neutral. First, models of all lines branching off the section are shaped and entered to a data base as values of longitudinal parameters of sections of a replacement circuit of all lines in a three-phase form. Then, after values of the measured phase voltages on buses and currents are obtained at the beginning of lines there set in turn are points (for example the end of each section) of possible damage along each line, values of complex phase voltages are shaped for each line at each set point, a minimum value of voltage modulus is found based on values of phase voltages at all points along all the lines, which corresponds to an earth fault point. A damaged line is a line, in which a value of voltage modulus is minimum. For more accurate determination of a damage place due to consideration of distributed parameters of lines, first, values of longitudinal and transverse parameters of U-shaped replacement circuits of sections of all the lines branching off the section and parameters of branches of the lines in the three-phase form are shaped. In order to determine a break place, a minimum value (close to zero) of current modulus is found based on values of phase currents in all ends of the sections of all the lines, which corresponds to a phase conductor break place. In order to ensure visual expression and comfort of operation, sections are chosen between two adjacent supports along a power transmission line.
EFFECT: reduction of labour input and improvement of accuracy at determination of a damage place in electrical networks with an insulated neutral due to more complete consideration of parameters of lines.
4 cl
