Abstract
Changes in soil electrical parameters can affect the distribution of earth potential in high-voltage direct-current (HVDC) ground electrodes when climatic conditions changes. This paper proposes a model to describe the relationship between surface-layer soil moisture and surface-layer soil resistivity under short-term climatic influence, by using image recognition technology. Based on the relatively stable resistivity of lower soil layers, a soil model more reflective of the actual operating conditions is established for soils near the ground electrode, and a finite element method is adopted to calculate the earth-surface potential (ESP). The experimental results indicate the following: (1) Compared with other measurement methods, image recognition of surface soil resistivity is a low-cost, real-time, online, and accurate method; and (2) changes in surface-layer soil moisture affect both ESP and step voltage. These effects are large in the case of high resistivity for the soil layer where the ground electrode is buried. This large fluctuation in step voltage particularly results in a potential safety hazards during ground electrode operation. Therefore, in order to ensure personal safety and obtain more accurate electrical parameters, it is necessary to consider the effect of natural climate on the soil surface resistivity. Finally, the value of the step voltage can be observed using image recognition, this also provides a new method for the safety monitoring of the DC ground electrode.
Highlights
The ground electrode in an high-voltage direct-current (HVDC) transmission system plays an extremely important role in maintaining safe and stable operation of the entire system
Because the ground current can have a negative impact on nearby power and communication equipment,[1,2] and the abnormal increase in step and touch voltages can cause personal injury and death,[3,4,5] it is necessary to establish a surface-potential calculation and monitoring model for HVDC transmission systems
The extent to which the calculated and actual electrical parameters of ground electrodes are close to each other is directly affected by the soil structure model
Summary
The ground electrode in an HVDC transmission system plays an extremely important role in maintaining safe and stable operation of the entire system. In view of the aforementioned context, when establishing a soil model, the effects of short-term climate (short-term rainfall and high temperature) on surfacelayer soil resistivity were considered for the first time, this study proposes an identification model for surface-layer soil resistivity based on soil image. Based on the relatively stable resistivity values of lower-layer soils, a complete soil-structure model is established for the soil near the HVDC ground electrode, considering the effects of soil moisture changes. A finite element method is employed to calculate the earth-surface potential and step voltage of the region near the ground electrode, and the effect pattern of surface-layer soil moisture changes on the earth-surface potential and step voltage is analyzed. The method used in this paper to identify resistivity, it can provide accurate parameters for establishing a soil model, and identify the step voltage through the soil image
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
