Fault Location Method for UHV Transmission Lines Based on Weighted Least Squares Algorithm

Abstract

The invention discloses a weighted least square algorithm-based ultra-high voltage transmission line fault positioning method. The method includes the steps of: establishing an ultra-high voltage transmission line distributed parameter model: according to distributed parameter characteristics of a transmission line, cascading and superposing voltage and current on infinite small segments of the transmission line to obtain the distributed parameter model; processing parameters in the ultra-high voltage line according to the established model, i.e., simplifying wave impedance Zc and a propagation coefficient r; calculating positive sequence, negative sequence and zero sequence voltage of a fault point according to sending end measured values, and calculating positive sequence, negative sequence and zero sequence voltage of the fault point according to receiving end measured values; introducing phase angle displacement delta to represent a displacement phase angle of the sending end lagging behind the receiving end, adopting a weighting method to allocate proportions of unmatched voltage components of the zero sequence, positive sequence and negative sequence, and determining a fault position based on the weighted least square algorithm. The method provided by the invention establishes the distributed parameter model of the ultra-high voltage transmission line, and reduces a model error caused by simple processing of a lumped parameter model adopted by a short line.

Description

technical field [0001] The invention relates to the field of fault location of UHV transmission lines, in particular to a method for fault location of UHV transmission lines based on a weighted least square algorithm. Background technique [0002] In recent years, since the construction of UHV transmission has become a broad consensus, my country will usher in a rapid development stage of UHV construction. By 2020, the State Grid will build a "five vertical and five horizontal" UHV AC backbone grids and 27 UHV lines. The research on the fault location method of UHV transmission lines in direct current transmission projects has become the focus of domestic and foreign scholars' research. Therefore, fault location of UHV transmission lines has become a concern of power system researchers and power equipment manufacturers. However, due to the impact of environmental factors such as lightning, rain, snow, typhoon and other harsh environments, and the characteristics of long dist...

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Problems solved by technology

[0007] 1. The traveling wave positioning method will produce misjudgments and missed judgments under individual fault conditions. The factors that affect its accuracy include the time delay of the current transformer and the speed of traveling waves, so there are usually certain errors in the calculation results.

[0008] 2. The positioning algorithm based on wave recording or protection has low accuracy, and the single-ended algorithm depends on the current and voltage phasor value of the single end of the line, and this method is rarely used in UHV lines

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