In order to improve the reliability and flexibility of energy storage in microgrid, an adaptive hierarchical control strategy considering energy storage SOC was proposed. Firstly, the operation state of energy storage was controlled by the sequence of battery voltage, bus voltage and energy storage SOC. Secondly, the State Of Charge (SOC) of energy storage was graded and the improved droop coefficient with continuous different changing trends was set. Then, the Microgrid Interconnect Converter (MIC) adopted the outer loop normalized power sharing control and the feed-forward inner loop current control. Finally, the AC-DC hybrid microgrid simulation model of fan, photovoltaic, energy storage and load were established to verify the effectiveness of the proposed strategy. The results showed that the proposed strategy can ensure the stability of frequency and voltage of the system when dealing with the changes of external environment.

The health status of 35kv switchgear directly affects the safe operation of subway. In view of the current problems of single feature quantity, inadequate detection elements and inaccurate overall state evaluation of switch gear, a state evaluation method for metro 35kv switch gear based on multi-feature quantity was proposed. The characteristic parameters such as transient ground voltage, ultrasonic value, cable joint temperature and bus temperature were determined by triangular fuzzy number method with constant weight. The variable weight method was introduced to ensure the balance of state evaluation, and the state evaluation of switch cabinet was carried out with matter-element extenics. The actual detection data of 35kv switchgear 8DA10 in a Shanghai metro substation is taken as an example to verify the effectiveness of the algorithm.