A method for measuring magnetic field strength near high-voltage transmission lines on hillsides

Abstract

The invention relates to a method for measuring and calculating magnetic field intensity near a high-voltage power transmission line on a mountain slope, and belongs to the field of field intensity measurement and calculation of electric magnetic fields. In the kth span, a standard coordinate system XYZ is established in a plane of the high-voltage power transmission line; in the kth span, a coordinate system X'Y'Z' is established in the plane of the high-voltage power transmission line; a catenary equation model of the high-voltage power transmission line is obtained; a transformation matrix model of the coordinate system X'Y'Z' and the standard coordinate system XYZ is obtained; through a Biot-Savart law, eddy is generated based on a current of the high-voltage power transmission line and a poor conductor of the ground; simplification is performed; the magnetic field intensity, defined in the specification, of any point, in the standard coordinate system XYZ, of the high-voltage power transmission line in the kth span is obtained; the magnetic field intensities in continuous three spans are superposed; and the magnetic field intensity, defined in the specification, of any point, in space, of the high-voltage power transmission line in the kth span is obtained. Compared to the prior art, the method considers an arc sag factor of the high-voltage power transmission line and can realize measurement and calculation of the magnetic field intensity of any point near high-voltage power transmission lines in different planes.

Description

technical field [0001] The invention relates to a method for measuring and calculating magnetic field strength, in particular to a method for measuring and calculating magnetic field strength near high-voltage transmission lines on hillsides. Background technique [0002] Since the 1970s, countries around the world have conducted many experimental studies on the impact of power frequency magnetic fields on ecology. Judging from the research reports, although no consistent conclusions have been obtained, there are many cases suggesting that long-term exposure to strong extremely low-frequency magnetic fields has increased the risk of malignant cancers such as leukemia, lymphoma, brain cancer, and breast cancer compared with the control group . Therefore, it is of great significance to study the distribution of magnetic fields near high-voltage power lines for the design of high-voltage power lines and to protect the safety of workers. In the existing calculation methods of ...

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Problems solved by technology

In the existing calculation methods of magnetic field strength, factors such as the sag of the transmission line and the span are mostly ignored, and the height from the ground at the lowest point of the sag or the average height of the line is used as the conductor height for calculation, and the transmission line is regarded as parallel to the ground A two-dimensional calculation model is established for an infinitely long straight conductor. Generally speaking, the UHV conductor has a large specific load due to its own weight, a large cross-section and a high erection, so the wind load and ice load are also relatively large, and it is significantly affected by the climate. These characteristics determine the special load. The sag of the high-voltage transmission line is relatively large, and the two-dimensional simplified model will produce large errors

There are a few other literatures that consider the sag factor of the transmission line, but only consider the magnetic field distribution near the high-voltage line built on the plane. For some high-voltage transmission lines built on complex terrain (such as hillsides), domestic and foreign There is no detailed description in the literature; in addition, in the literature searched, only the situation that the high-voltage transmission lines are on the same plane is considered, and the situation that there is an angle between the high-voltage transmission lines is not discussed

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