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Oil immersed power transformer is the most widely used large power transformer in power system and its insulation structure is mainly composed of oil, paper and other solid insulation materials. Partial discharge monitoring is an effective means to find dielectric faults of transformer in an early stage of development. Ultra-high frequency(UHF) partial discharge detection technology has high detection frequency and strong anti-interference ability, which is suitable for transformer online detection. In this paper, five typical transformer discharge models are built, and the discharge spectra of each model are measured by a UHF sensor. The test results show that the surface discharge and wedge discharge most occurs near the voltage peak, the discharge phase distribution of floating part discharge is very wide, the internal air gas discharge mostly occurs in the area where the absolute value of voltage increases, and the point-to-plane discharge has a typical polarity effect.

The coal storage yard of thermal power plants are exposed to the air, causing problems like polluting the environment, falling short of requirements of eco-protection and undermining safe production. It causes threats in three forms:coal dust, coal pile explosion, and coal pile spontaneous combustion. Wind and dust suppression walls, dry coal sheds, fully enclosed coal sheds and other measures can be used in these yards to prevent pollution in the yard. Pollution treatment in these yards can avoid static dusting of coal and reduce the spread of dynamic dusting. This study interpreted the necessity of environmental treatment of coal storage yards and the development of three main technologies, and conducted detailed analysis and discussion of various environmental treatment solutions for coal storage yards of thermal power plants. This study intends to provide experience and lessons for environmental treatment of coal storage yards.