Distance protection system suitable for half-wavelength power transmission line and control method thereof

Abstract

The invention relates to a distance protection system suitable for a half-wavelength power transmission line and a control method thereof. The distance protection system comprises a comprehensive distance protection unit, and at least two segmentation protection units which are arranged between the beginning end and the tail end of a power transmission line and at a certain distance from the two ends. A certain distance is reserved between any two adjacent segmentation protection units. Each segmentation protection unit is used for receiving electric quantity information of a corresponding segmentation point on the power transmission line and calculating impedance information of the corresponding segmentation point. The outputs of all the segmentation protection units are connected with the comprehensive distance protection unit. According to related information sent by the segmentation protection units, analysis and determination are carried out, and corresponding signals are output, so as to protect the power transmission line. The use of the system for relay protection can solve problems of protection action resistance due to the extremely large measurement impedance in the middle of the line, and protection malfunction due to the measurement impedance being close to a fault of a beginning end in case of an outer fault at a far end of the line.

Description

technical field [0001] The invention relates to a distance protection system suitable for half-wavelength transmission lines and a control method thereof. Background technique [0002] With the construction of energy Internet, half-wavelength power transmission technology, as an efficient long-distance intercontinental power transmission method, has a good application prospect. Long-distance, large-capacity power transmission is inevitable. For example, the distance from some thermal power / hydropower energy bases in the west to the coastal load center is about 3,000 kilometers, and the power transmission distance is just close to the power frequency half-wavelength range. Therefore, half-wavelength power transmission technology can be considered as a solution for these large-capacity power transmissions. [0003] UHV half-wavelength transmission lines have a long transmission distance, and the electrical characteristics are quite different from existing UHV lines. The tradi...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a distance protection system and its control method suitable for half-wavelength transmission lines to solve the problem that traditional distance protection methods cannot effectively protect long-distance transmission lines

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