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The corridor of the high-voltage direct current transmission lines in China is very complex and there may be buildings near the lines. The conductivity of the building material may influence the electric field in the building. In this paper, based on the upstream FEM, a method is proposed to solve the coupled problem of the ion flow field in the air and the current field in the building model. The numerical results coincide with the analytic results and measurement results. The electric field in and on the building model is analyzed considering different conductivities. [ABSTRACT FROM PUBLISHER]

The ac-dc hybrid transmission line is an effective way to enhance the transmission capacity of a power corridor. However, the corona discharge of ac and the dc transmission lines may interact with each other, which makes the electric field at the ground level difficult to be predicted. This paper presents a simulation method for the calculation of the field effects caused by the corona activities of hybrid ac-dc transmission lines. This approach can simulate the convection and recombination of the space charge generated by ac or dc corona without improper simplifications, and the conductor surface gradient strictly kept to the onset value. The calculated electric field and ion current density at the ground level agree well with the measurement results of a hybrid line model. [ABSTRACT FROM PUBLISHER]

As many high voltage direct current (HVDC) projects are constructed in China, the ionized field problem is of wide concern. The upstream finite element method (Upstream FEM) has good adaptability and is widely used to analyze the ionized field under HVDC lines. Galerkin's scheme is used to improve the charge density precision. Poisson's equation solution technique and charge density updating strategy are adopted to accelerate the calculation. The charge density precision and the calculation efficiency is remarkably improved. For the 15\,000-nodes-scale ionized field problem of bipolar-6-bundled HVDC lines, the calculation time is less than 5 s. The algorithm also shows good robustness to the charge density initial value in the numerical cases. [ABSTRACT FROM PUBLISHER]

The ionized field under HVDC transmission lines is actually a 3-D field with considering the influence of wires sag, towers, up-and-downs on the ground, surrounding buildings and other situations and little of its calculation method has been reported. In this paper, a method to calculate the 3-D ionized field under HVDC transmission lines is proposed based on Deutsch's assumption which is simple, fast, and easy to use and the computation cost of which is low. After the validity of the method is testified, some examples are analyzed and some conclusion are given. [ABSTRACT FROM PUBLISHER]

A modified method based on the optimized charge simulation method (CSM) is used to predict the corona onset voltage and electric field when the space charges due to the corona are considered. Based on the streamer model of corona discharge, space charges generated near the conductors are predicted. In order to calculate the electric field at the conductor surface, space charges are replaced by some equivalent line charges near the conductor. Because of the existence of space charges, the corona onset electric field is changed a little. After a simplified model of actual power transmission lines is introduced with the help of rough coefficient, the corona onset voltage and corona onset electric field are calculated for different types of conductors finally. [ABSTRACT FROM PUBLISHER]