Solving method for transmission equation of complex same-tower multi-loop transmission line

Abstract

The invention discloses a solving method for a transmission equation of a complex same-tower multi-loop transmission line. The solving method comprises the following steps of: S1) establishing line models in a segmentation manner according to different physical parameters of the transmission line, wherein the line models comprise same-tower line models with strong coupling relationships and non-same-tower line models with weak coupling relationships; S2) solving a segmented electric parameter matrix of each loop according to the established line models; S3) solving a full-line unit-length average self-induction parameter matrix and a unit-length average self-capacitance parameter matrix of each loop; S4) performing normalization processing on the loops, and performing equivalence on the loops to form multi-conductor transmission lines with same length; and S5) substituting the multi-conductor transmission lines into lossless multi-conductor transmission line equation to solve the transmission equation of the same-tower multi-loop transmission line according to boundary conditions of the transmission loops of the transmission line. According to the solving method, as the parameters of the complex transmission line are subjected to the normalization processing, the complex same-tower multi-loop transmission line can be solved by the conventional multi-conductor transmission line equation.

Description

technical field [0001] The invention relates to the field of steady-state calculation and analysis of multi-circuit complex transmission lines on the same tower in a power system, in particular to a solution method for normalizing parameters of multi-circuit transmission lines on the same tower. Background technique [0002] With the rapid development of power grid construction, transmission line corridors are becoming more and more dense, and more and more parallel multi-circuit transmission lines are erected on the same tower. The resulting complex alternating electromagnetic field environment may cause serious three-phase line parameter differences between lines. balance problem. The unbalanced parameters of the three-phase line will cause the asymmetry of the three-phase current. In severe cases, the current value of one phase line will be several times that of the other phase, which will greatly reduce the transmission capacity of the line, increase the loss of the line...

AI Technical Summary

Problems solved by technology

The unbalanced parameters of the three-phase line will cause the asymmetry of the three-phase current. In severe cases, the current value of one phase line will be several times that of the other phase, which will greatly reduce the transmission capacity of the line, increase the loss of the line, and easily cause the zero-sequence current of the line to overshoot. large, resulting in zero-sequence protection action, line tripping and other accidents

However, for a long time, since the optimal phase sequence arrangement of multi-circuit transmission lines involves many fields, especially for more complex transmission lines, it is difficult to solve the transmission equation, and there has been no effective analysis method in engineering practice

Multi-circuit transmission lines on the same tower or parallel to each other are essentially a multi-conductor transmission line system with electromagnetic coupling. However, the traditional multi-conductor transmission line equation is suitable for solving multi-conductor transmission line systems with uniform transmission lines. However, the actual transmission system line layout is relatively complex. Complicated, such as the situation of the same tower in different sections of transmission lines is different, that is, the number of loops of the same tower changes or changes from the same tower to different towers, different tower types are selected for different terrains, the line types of different sections of conductors are different, and some lines are close to parallel or cross. crossing phenomenon, so the traditional multiconductor transmission line equation cannot be directly applied to solve

In view of this situation, the present invention proposes a line parameter normalization processing method to eliminate the disadvantage that the traditional multi-conductor transmission line equation cannot be directly applied to solve complex lines

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