A Calculation Method of Unbalanced Degree of Multi-circuit Transmission Lines on the Same Tower

Abstract

The invention relates to a computing method of unbalancedness of multi-circuit power transmission lines on the same tower. The method comprises the steps of computing the initial impedance and admittance matrix of each line according to the conductor type, conductor division method, pole and tower type and lightning conductor connecting method of each power transmission line; selecting electric parameters and building a model of the multi-circuit power transmission lines on the same tower based on computing results in the PSCAD / EMTDC environment; setting a short circuit and an open circuit of the tail end of each power transmission line, computing the current value of the short circuit of the tail end of each power transmission line and the current value of the open circuit of the tail end of each power transmission line, and obtaining sequence components of the current of the short circuit of the tail end of each power transmission line and the open circuit of the tail end of each power transmission line by means of the symmetrical component method through conversion; computing the electromagnetism and static electricity unbalancedness of the multi-circuit power transmission lines on the same tower based on the sequence components of the current of the short circuit of the tail end of each power transmission line and the open circuit of the tail end of each power transmission line. The computing method of the unbalancedness of the multi-circuit power transmission lines on the same tower is capable of computing the unbalancedness of the multi-circuit power transmission lines on the same tower comprehensively, accurately and conveniently and provides theoretical guidance for optimal design and operation of the multi-circuit power transmission lines on the same tower with different voltage classes, different pole and tower types and different phase sequence arrangement methods.

Description

technical field [0001] The invention relates to a research on unbalanced power, in particular to a calculation method for the unbalanced degree of multi-circuit transmission lines on the same tower. Background technique [0002] With the rapid development of my country's power grid construction, transmission line corridors are becoming more and more scarce. As a new type of power transmission, multi-circuit transmission on the same tower has been widely used nationwide. Due to the asymmetry between the lines and the position of the lines to the ground in the multi-circuit transmission on the same tower, the mutual inductance between the lines is asymmetrical, resulting in the three-phase asymmetry of the line. The three-phase asymmetry of the power system will adversely affect electrical equipment such as generators, relay protection, and transformers, resulting in reduced power quality at the user side and increased line losses. Calculating and analyzing the unbalance degr...

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Problems solved by technology

[0004] The present invention aims at the problem of unbalanced degree of multi-circuit transmission lines on the same tower at home and abroad, and proposes a calculation method for the unbalanced degree of multi-circuit transmission lines on the same tower. Considering the influence of different connection methods of lightning conductors on line parameters, it is proposed that the characterization is not The calculation method of the measurement index of the physical nature of the balance degree, and the unbalance degree of the multi-circuit transmission line on the same tower with the help of professional software PSCAD / EMTDC simulation, can be used for multi-circuit transmission lines on the same tower under different voltage levels, different tower types, and different phase sequence arrangements. Provide theoretical guidance for the optimal design and operation of transmission lines, which is practical, accurate and convenient

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