Integrated energy system (IES) has attracted wide attention as an efficient solution to a comprehensive utilization of hybrid energy system including electricity, heat, and hydrogen in recent years. This paper investigates the stochastic optimal operation for the micro integrated electric power, heat, and hydrogen delivery system. Firstly, the mathematical model of the micro integrated energy system for residential communities and other similar scenarios is discussed, including the energy interface, power microgrid, micro-heat system and micro-hydrogen system with considerations of distributed energy supply, energy storage, load, upstream energy network interface and their mathematical models. Secondly, the correlated uncertainty, such as wind power, solar power, and loads, are considered and handled in micro integrated energy system. Finally, a scenario-based approach is proposed for the stochastic operation of micro integrated energy system. The objective function is formulated to minimize the expected total operation and environmental costs, the hourly schedule of controllable components in micro integrated energy system. Numerical results demonstrated that the effectiveness of the proposed method. The correlated uncertainty and the corresponding impacts are accurately presented in the optimization model.

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High voltage direct current (HVDC) transmission system has the advantages of large capacity, long distance and low loss. Relying on the advantages of HVDC transmission, China has established a large-scale energy transmission channel in the west, effectively solving the problem of uneven local energy distribution. However, HVDC transmission will generate ground current when it is operating in a single pole, which will cause the DC bias effect of the transformer. At this time, the core magnetic circuit of the transformer is saturated. Transformers will experience increased vibration, increased noise, local overheating, and surge in harmonics. This paper, based on the Jinhua HVDC transmission project as a background, established a power grid topology model in Zhejiang area based on the field-circuit coupling method. The focus is on calculating the DC bias of Shenze transformers in Jinhua area, and proposing treatment measures based on the calculation results. According to the actual measurement of the project, the accuracy of the calculation result is verified, which reflects the effectiveness of the governance measures.

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