TDCM (three-dimensional combined-layer soil model)-based transformer substation ESP (earth surface potential) calculation and address selection detection method

Abstract

The invention provides a TDCM (three-dimensional combined-layer soil model)-based transformer substation ESP (earth surface potential) calculation and address selection detection method. The method comprises the following steps of constructing a TDCM according to a soil structure of an area in the vicinity of a high-voltage direct current power transmission grounding electrode; constructing a Green function of a current point source according to the TDCM by utilizing a fitting mirroring method; deducing a potential expression according to the TDCM-based Green function, and calculating a transformer substation ESP distribution diagram by virtue of ESP calculation software; further calculating the magnitude of direct current flowing through a neutral point of a transformer; comparing a value of the direct current with a direct current bias threshold value of the transformer, and judging whether the transformer is threatened by direct current bias or not. According to the method, a theoretical basis is provided for accurately evaluating the magnitude of the direct current flowing through the neutral point of the transformer, the reasonability of transformer substation address selection in the vicinity of the direct current grounding electrode is ensured, support is provided for a control measure over a transformer substation with direct current bias, and the method is significant for the reasonable planning of an ultrahigh-voltage alternating current and direct current hybrid power grid and control over the direct current bias.

Description

technical field [0001] The invention relates to the technical field of substation surface potential calculation and detection, in particular to a TDCM model-based substation surface potential calculation and location detection method. Background technique [0002] In terms of long-distance, large-capacity power transmission and power system networking, high-voltage direct current transmission has obvious advantages, and plays an important role in the adjustment of my country's energy structure and the "West to East Power Transmission" project. However, when HVDC power transmission adopts a single-pole ground loop operation mode, the strong direct current into the ground causes uneven distribution of Earth Surface potential (ESP), and part of the DC current enters the AC transmission system through the neutral point of the grounded transformer, causing The DC bias of the transformer, the iron core is highly saturated, and the magnetizing current is severely distorted, resulti...

AI Technical Summary

Problems solved by technology

Due to the slow convergence speed of the classic mirror image method, it is not capable of deriving TDCM Green's function; because the complex mirror method introduces concepts such as complex distance and angle, which greatly increases the computational complexity, and the position and intensity of the mirror image are complex numbers, physics The meaning is ambiguous, so the application is quite limited

The above reasons limit the exact solution of any multi-layer TDCM Green's function, resulting in severe distortion of the evaluation of the DC flow passing through the neutral point of some transformers, resulting in unreasonable power grid planning schemes and DC bias control measures

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