Fault detection method for transverse differential protection of parallel transmission lines on the same poles based on impedance ratio

Abstract

The invention discloses a fault detection method based on impedance ratio same-tower power transmission line transverse differential protection. The method includes the following steps: when faults happen in a power transmission line, fault phases in which the faults happen are selected; according to the phase selection result, data measurement of electrical quantities is carried out on the fault phases and when the faults happen in the fault phases, the measurement data includes bus voltages of all fault phases and currents of first loop lines and second loop lines of all fault phases; according to the measurement data, measurement impedance of each wire in the fault phases is obtained; according to the measurement impedances, impedance ratio transverse differential values of the measurement impedances of the fault phases are obtained; when the impedance ratio transverse differential values are larger than an impedance ratio transverse differential criterion set value, it is judged that same-tower line internal faults happen; and when the measurement impedance values of the first loop lines are larger than the measurement impedance values of the second loop lines, it is judged that the faults happen in the second loop lines; and otherwise, it is judged that the faults happen in the first loop lines. The fault detection method based on impedance ratio same-tower power transmission line transverse differential protection adopts an impedance ratio transverse differential criterion to detect the faults of the same-tower power transmission lines so that effects of operation method change of a system on a protection range can be effectively weakened so that a successive action area can be reduced.

Description

technical field [0001] The invention belongs to the field of electric power systems, and more specifically relates to a fault detection method based on the impedance ratio of parallel transmission lines with parallel transmission lines. Background technique [0002] Traditional cross-connection differential protection is mainly used for parallel double-circuit lines. Its basic principle is to compare the current of double-circuit lines on the same side without adding additional protection communication channels. According to whether the direction of the current is introduced into the action criterion, the transverse differential protection can be divided into two forms: the differential protection in the transverse direction and the current balance protection. The current balance protection only compares the currents of the two circuits, and is suitable for installation on the power side of parallel double-circuit lines powered by a single-side power supply, but not for the ...

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Problems solved by technology

[0005] Aiming at the defects of the prior art, the purpose of the present invention is to provide a fault detection method based on the impedance ratio-based cross-connection differential protection criterion of parallel transmission lines on the same pole, aiming to solve the problem of the current cross-connection differential protection. The technical problem that the sequential action area is too large when the lines are paralleled on the same pole

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