Research Of The Power Frequency Magnetic Fields Distribution Around Dry-Type Air-Core Reactor

As an electrical product with good linearity, starting voltage distribution uniform, easy to maintain the good performance, dry-type air-core reactors have been widely used at home and abroad. Because of the special structure of these reactors, the strong magnetic field (especially for current limiting reactors, and other terms of big current reactors) will be generated around them in the running, or even cause misoperation. At the same time, the occupational exposure and the public exposure under the strong magnetic field have also become common concern issues of environmental protection and power industry. A magnetic field calculation model of dry-type air-core reactor considering the effect of eddy current was proposed in this paper, based on in-depth understanding basic structure and working principle of dry-type air-core reactors. Then, analyze and summarize simulation results to identify magnetic field distribution around air-core reactors, and propose the reference which have important meaning to reactor's design and installment.First, studied and analyzed existing magnetic field calculation method of air-core reactors. A mixed finite-element(FE) model for 35kV dry-type air-core reactor group of 500 kV Substation in Chongqing, which considered the effect of eddy current, was proposed for calculation of magnetic fields. According to the analysis of this model, 7 times of the air-core reactor group region was suitable for calculation region, then simulation the magnetic field around the reactor group. Then, measured the magnetic field of 35 kV reactor group in 500 kV Substation in Chongqing, the comparison between calculation results which taking into account the impact of eddy current or not and measured values showed that the mixed finite-element method model may assess the magnetic field distribution around air-core reactors.Finally, identified magnetic field distribution around single-phase and three-phase air-core reactors, simulated magnetic field distribution around air-core reactors when change the technical parameters and install ways, and proposed the reference which have important meaning to reactor's design and installment.The mixed finite-element method model may assess the magnetic field distribution around air-core reactors and provide theoretical basis for type and installation way of air-core reactors for power department. On the other hand, based on the magnetic field distribution around air-core reactors, an early-warning mechanism can be established, which can provide safeguard for the safe operation of other electronic equipment and the substation employee.