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In order to effectively reduce and retard corrosion of the power transmission and transformation equipment in Chengdu power grid and to improve power supply reliability, Q235 carbon steel material which is the most widely used metal material in power grid was selected as the targeted research object in this article. Exposure experiments were performed in urban atmospheric environment of Chengdu city in the southwest region of China. The corrosion behavior of Q235 carbon steel material was investigated at different seasons. The macro- and micromorphologies after corrosion were observed using a digital camera and scanning electron microscopy (SEM), respectively. Element distribution of the rust layer and the corrosion products was characterized by energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR); the corrosion mechanism was also briefly analyzed.

In recent years, with the advantages of long distance and large capacity, ultrahigh voltage direct current (UHVDC) transmission projects are developing increasingly in China. Also UHVDC transmission projects share corridors with underground oil & gas pipelines has become increasingly prominent. UHVDC ground electrode influences underground oil & gas pipeline is a new problem in China with rapid development of the electric power and oil-gas industry. When the UHVDC transmission system is working under mono-pole ground return operation mode, a high magnitude ground current will be injected into the soil through the ground electrode. The injected current will cause corrosion effect on the underground metal facilities such as oil & gas pipelines around the UHVDC ground electrode. In this paper, the influence of the ground return current of the UHVDC ground electrode in mono-pole ground return operation mode on the metal pipelines around the UHVDC ground electrode has been studied. The electrolytic corrosion principle of the underground metal pipelines caused by the ground electrode current was discussed. Then several protective measures were elaborated in detail. The research can give useful guideline to the corrosion influence of the UHVDC ground electrode current on the metal pipelines and can provide protective measures for the metal pipelines. It can also be applied in design, planning and site selection periods for new UHVDC ground electrode.

Market demands on the product performance and additional service of oil-immersed distribution transformer have become increasingly diversified. Single form of oil-immersed distribution transformer product and pure business relationship cannot adapt to current needs. Product service system innovation design can change single product form to the combination of product and service, it has the significance of further satisfying user requirements, and it is an extension service in a new form of physical product. In this paper, according to Kano model, user requirements were collected and classified. Then based on analytic hierarchy process (AHP), each class of user requirements was sorted by optimal weight and recombined. Finally, user requirements were mapped into correlative function/service characteristics, innovation design of oil-immersed distribution transformer product service system was achieved. The results have a certain guiding role for transformer manufacturers to adapt to the demands of power supply enterprises.