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The government of China commits to achieve peak carbon dioxide emissions by 2030. According to the United Nations Environment Programme, nearly 40% of energy-related carbon dioxide emissions are attributable to the building sector while building operations account for over 70% of carbon emissions. How to quantitatively analyze the factors related to operational carbon emissions under the circumstance of rapid growth of data volume is the key problem to be solved. This article explored the main factor affecting carbon emissions of commercial office buildings based on data mining and analyzed all carbon sources using the variation and deviation method in the city of Beijing, China. It is found that electricity, trains, airplanes, and hotels have a great impact on the building’s operation stage carbon emission, and targeted carbon emission reduction policies and measures can be made to reduce the sample’s carbon emission.

High voltage direct current (HVDC) cable accessories are usually the weak link in the cable system for the electric field distribution is often extremely uneven, and it has a range of adverse effects in design and manufacture. In this paper, Ethylene-propylene-diene terpolymer (EPDM) was developed for ±525 kV HVDC cable accessories, and the conductivity, XLPE/EPDM interface charge behavior and breakdown strength were tested respectively. The electric field distribution of cable accessories was calculated by COMSOL analysis software. It is shown that the conductivity of EPDM is nonlinear with electric field, and it is possible to achieve the uniformity of electric field distribution by using a composite material with nonlinear conductive properties. Furthermore, the interfacial charge characteristics of XLPE/EPDM depend on the conductivity of EPDM. As a consequence, the research will make a potential application for ±525 kV HVDC cable accessories.

Ultra high voltage(UHV) power cable system is an economical, safe and reliable power transmission mode. In recent years, the concern about the traditional fossil energy pollution in the world and the determination to using clean energy have promote the medium distance UHV submarine power cable system. This paper designs and tests one kind of energy saving and loss reducing conductor applied to large cross-section submarine cable. Through reasonable process control, the paint film on the enamelled wire surface can be avoided being scraped during the process of twisting. According to the measured AC / DC resistance ratio, the optimized design for the subsequent conductor is put forward. Compared with the traditional conductor, the current carrying capacity of the conductor is improved, and it has a positive and practical significance for reducing the Joule loss of the cable system.

In recent years, with the rapid development of large-length ultra-high-pressure voltage extrusion insulated submarine cable technology, the cable system in the medium-length offshore power grid interconnection project has been gradually replaced by XLPE insulation by traditional oil-paper insulation. There are many large cross-section conductors used in long-distance power transmission cables, and according to the IEC 60287-1-1, it is recommended to use Milliken conductors to reduce the AC resistance of conductors, at the same time, in submarine cables, there is a high requirement on the water-blocking performance of conductors and the water resistance of Milliken conductors is poor, so it is not used in submarine cable conductors. This paper puts forward a layering enamelled stranded conductor and a calculation method of AC / DC resistance ratio for it. The validity of the calculation method is verified by experimental tests. At the same time, the calculation shows that the AC / DC resistance of the conductor at 1800 mm2 nominal cross section can be reduced by 16% compared with the conventional round compacted conductor in the prior art. The effectiveness of this conductor in reducing AC resistance is verified by finite element simulation.