Protection performance evaluation system and method at same-tower four-circuit power transmission line

Abstract

The invention discloses a protection performance evaluation system and method at a same-tower four-circuit power transmission line. The method comprises: inputting a line structure parameter, access grid information and protection incorrect evaluation factor; controlling turning on or off of all switches of a first group to a fifth group of fault switches to realize controlling of a fault type; for any fault type, setting line lengths and fault point positions between double circuit towers and four-circuit towers; according to voltage levels and locations of all power supplies, adjusting parameters of corresponding transformers and impedors; and carrying out statistics of fault types and line protection actions at occurrence of faults at different positions and carrying out weighted statistics and evaluation on faults and protection actions of all power transmission lines, thereby obtaining a line protection performance quality evaluation report. According to the invention, various fault feature influence factors are considered comprehensively; some operation ways that may cause inaccurate protection actions easily can be avoided; protective setting and key prevention are realized; protection strategies of manufacturers can be protected; and the good support can be provided for secure and stable operation of the power grid.

Description

technical field [0001] The invention relates to the field of AC high-voltage transmission systems, in particular to a protection performance evaluation system and method on a four-circuit transmission line on the same tower. Background technique [0002] The erection of the same tower is an effective measure to increase the transmission capacity of the transmission corridor and reduce the cost of transmission line erection. The increasingly tense transmission corridors of the power system have led to an increasing number of transmission lines on the same tower. Most of the early lines on the same tower were double-circuit lines paralleled on the same tower throughout the entire process. However, due to the constraints of many conditions in the planning and construction of the power grid, and the restrictions on the outlet corridors near the substation, the erection of lines on the same tower was varied, and many parts appeared. In the case of erecting double-circuit lines o...

AI Technical Summary

Problems solved by technology

Most of the early lines on the same tower were double-circuit lines paralleled on the same tower throughout the entire process. However, due to the constraints of many conditions in the planning and construction of the power grid, and the restrictions on the outlet corridors near the substation, the erection of lines on the same tower was varied, and many parts appeared. In the case of erecting double-circuit lines or multiple-circuit lines on the same tower, the geographical information, operation mode and fault types are becoming more and more complicated

The research on the relay protection technology of lines on the same pole is almost all aimed at parallel lines on the same pole throughout the whole process, but in fact, the derivative type of parallel lines on the same pole is more widely used in actual engineering, such as parallel lines on the same pole with different voltage levels However, due to the different erection methods, it is difficult to apply the current research results of single-circuit lines and lines paralleled on the same pole throughout the whole process directly to parallel lines erected on the same pole throughout the whole process.

Due to the existence of mutual inductance between lines, there is a large gap between the calculated value of short-circuit current and the actual value, which greatly increases the difficulty of fault analysis

In actual field work, the zero-sequence mutual inductance is often ignored to simplify the processing, resulting in a large difference between the calculated value of the fault current and the actual value, and the relay protection device configured based on this may lose its protective effect

The theoretical analysis of the fault characteristics of the complex same-tower line is extremely difficult. Even if the analytical expression of the line fault can be obtained through the complex fault analysis method, it is difficult to be directly used for protection performance analysis due to its complexity

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