Accurate user-transformer connectivity relationship (UTCR) plays a key role in fine management of low-voltage distribution network (LVDN) i.e., load expansion, line loss management, and electrical service restoration after outage. Limited data and low discriminability and noise in data increase the difficulty to identify UTCR for the existing data analytics methods. To overcome these hurdles, this paper proposes a novel UTCR algorithm which combining the data preprocessing with multi-dimensional priori knowledge based on voltage characteristics in LVDN. Firstly, the prior knowledge related to UTCR are refined on account of voltage correlation characteristics of users at different locations to provide theoretical foundation. Then, Z-score and principal component analysis are combined to standardize and extract features from the original voltage data to magnify the differences between data and reduce the impact of data noise. Further, on the basis of the prior knowledge of voltage correlation characteristics, a knowledge-driven identification model is proposed to identify users with wrong UTCR and their real UTCR. Finally, the performance of the proposed algorithm is verified on simulated LVNDs. The comparison analysis between the proposed method and other published methods and the impact of the number of principal components on the identification accuracy are also investigated. The results indicate that the proposed method achieves higher recognition accuracy than other published methods with low discriminability and noise in data.INDEX TERMS User-transformer connectivity relationship identification, low-voltage distribution network, data pre-processing, voltage correlation characteristics, knowledge-driven approaches

To bridge the gap that exists in the key equipment of the new subsea production control system, the all-electric subsea gate valve actuator, and exploit subsea oil and gas resources with high reliability and safety while saving energy, this paper proposes a novel concept prototype of an all-electric subsea gate valve actuator which has the key functions of a redundant drive, failsafe closing, auxiliary override, position indication, and low-power position holding. It satisfied the electrically-driven requirements of the subsea gate valves and achieved Safety Integrity Level 3. The prototype was developed and tested successfully. The all-electric subsea gate valve actuator is suitable for controlling subsea gate valves with various sizes and rated working pressures to minimize the power consumption for the purpose of keeping the valves open and safely closing them in the event of the electrical failure. An override and position-indicating mechanism is equipped for emergency operation and the visual indication of the status of subsea gate valves.

Banana mechanical crown cutting tool which is a critical component of banana crown cutting machine is designed and studied in this paper. Experiments were designed to optimize parameters of the cutting tool. Indexes are cut surface quality grade of banana crown, maximum cutting force and useful power consumption. For banana preservation, get high grade of cut surface quality is more significant than consume less energy. Results of experiments show that the optimum parameters are as follows: cutting speed is about 50–60 mm/s, number of cut sets are about 4–6, angle between thick cutter and axis of banana rachis is about 5°, width of thick cutter is about 8–14 mm, thickness of thick cutter is about 2–3 mm, edge angle of thick cutter is between 20° and 30°, width of thin cutter is about 10–14 mm and thickness of thin cutter is about 0.2–0.4mm. This study helps to make the completely mechanical postharvest treatments for banana postharvest treatments.