Electromagnetic Interference Analysis Of Distributing Tranformer In Subway Substations

With the continuous development of society and the increment of population mobility, people’s needs of convenient transportation are more and more intense. In recent years, as one kind of important urban rail traffic tool, subway developed rapidly. However, as a result of large-scale construction of urban railways, kinds of electric power equipments gathered in substation. Substation became a complex electromagnetic environment with concentrated distribution of strong or weak electric equipments.In substation, in order to give consideration to radiation limits, immunity and other factors between equipments, especially to avoid EMI between main substation and communication and signal facilities, rooms for electrical and mechanical equipments are arranged dispersedly, or rooms for strong and weak devices are assigned separately, generally in different sides of station or in varying floors. In this way, land resources are wasted. Electromagnetic Compatibility-EMC research on Wuxi urban rail’s co-constructed equipments in Passenger substations is presented to save land resources and construction cost, which not only makes distance between equipments closer, but also keeps them work normally. This is a bold attempt and innovation in domestic subway construction.In this case, it’s meaningful to analyze electromagnetic environment in substation, especially EMI of heavy current equipments, which not only helps to deepen understanding of whole environment, but also provides theoretical basis of protecting surrounding environment and sensitive devices. Besides, it’s an indispensable part of the "EMC research on urban rail’s co-constructed equipments in substations" Distribution transformer is a kind of useful equipments, mainly as power supply for lighting and dynamics. Besides, in rough test, acting as a heavy EMI resource, the value of its field strength is great. Therefore, this paper discusses how transformer causes EMI and is finished by theoretical analysis, field test combined with simulation.According to EMC theories, this paper states the EMI mechanism in substations. And on the basis of basic structure of transformer, from the point of view of transmission way, this paper conducted study from conduction interference and radiation interference, namely harmonic and electromagnetic field interference. Harmonic analysis is launched by equivalent circuit for technical parameters, Matlab for transformer modeling, and analysis of harmonic component. Electromagnetic field analysis is proceeded by three-dimensional simulation with CST, which is modeled with finite integral technique, and field test. Finally, the research’s value in engineering application is put forward, so as to some simple protective measures.