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The area of high voltage direct current (HVDC) transmission line is very large, so using cable for electric field monitoring system is very inconvenient. Wireless sensor network (WSN) can solve this problem. Compared with the traditional communication network, WSN has the advantages of small volume, high flexibility, strong self-organization. So it’s more suitable for the construction of distributed electric field monitoring system which has long distance and high mobility. On the other hand, optical E-field sensors are passive devices and they have such advantages as compact structure, wide-band response and wide measuring range which mechanical sensors lack. A distributed wireless system with optical E-field sensor is designed for collecting and monitoring the electric field under HVDC transmission lines. This measurement system has been used in China’s state grid HVDC test base and power transmission projects. Based on the experimental results, this measurement system demonstrates that it can adapt to the complex electromagnetic environment under the transmission lines and can accomplish the accurate, flexible, and stable demands of the electric field measurement.

This paper presents a new method for calculating the insulation health index (HI) of oil-paper transformers rated under 110 kV to provide a snapshot of health condition using binary logistic regression. Oil breakdown voltage (BDV), total acidity of oil, 2-Furfuraldehyde content, and dissolved gas analysis (DGA) are singled out in this method as the input data for determining HI. A sample of transformers is used to test the proposed method. The results are compared with the results calculated for the same set of transformers using fuzzy logic. The comparison results show that the proposed method is reliable and effective in evaluating transformer health condition.

Aiming at the paroxysmal fault of aircraft power system, this paper proposes a new method based on inverse problem of fuzzy optimization and deduces the corresponding fault diagnosis model. Firstly, establish the hybrid model of aircraft power system by Petri net. Secondly, analyze the relationship between fault symptoms and fault causes. Thirdly, combine the inverse problem with fuzzy diagnosis theory and get the inverse problem model of fuzzy optimization, the problem of diagnosis amounts to solving a fuzzy relational equation. Finally, solve the fuzzy relational equation by the numerical analysis method and do fault diagnosis by several fuzzy diagnosis rules. A case study demonstrates that the proposed model is feasible.

The power transformer is one of the most critical and expensive components for the stable operation of the power system. Hence, how to obtain the health condition of transformer is of great importance for power utilities. Multi-attribute decision-making (MADM), due to its ability of solving multi-source information problems, has become a quite effective tool to evaluate the health condition of transformers. Currently, the analytic hierarchy process (AHP) and Dempster–Shafer theory are two popular methods to solve MADM problems; however, these techniques rarely consider one-sidedness of the single weighting method and the exclusiveness hypothesis of the Dempster–Shafer theory. To overcome these limitations, this paper introduces a novel decision-making model, which integrates the merits of fuzzy set theory, game theory and modified evidence combination extended by D numbers, to evaluate the health condition of transformers. A four-level framework, which includes three factors and seventeen sub-factors, is put forward to facilitate the evaluation model. The model points out the following: First, the fuzzy set theory is employed to obtain the original basic probability assignments for all indices. Second, the subjective and objective weights of indices, which are calculated by fuzzy AHP and entropy weight, respectively, are integrated to generate the comprehensive weights based on game theory. Finally, based on the above two steps, the modified evidence combination extended by D numbers, which avoids the limitation of the exclusiveness hypothesis in the application of Dempster–Shafer theory, is proposed to obtain the final assessment results of transformers. Case studies are given to demonstrate the proposed modeling process. The results show the effectiveness and engineering practicability of the model in transformer condition assessment.

In order to collect the corona current in multiple locations of HVDC transmission lines, a distributed synchronous data acquisition system is designed and implemented. The system comprises a time server and a plurality of subsystems, the time server and the client computers in subsystems form a local area network through a switch. The distributed synchronous data acquisition system is designed based on NTP(Network Time Protocol), the Client/Server work mode is used in the system. At regular intervals, the time synchronization between clients and server is executed, the server sends collection command to each subsystem. The synchronization scheme of the corona current measurement system is realized by the software programming of the server and the client, and the synchronization precision can reach 1.725ms, which provides a solution for the large-scale distributed synchronous data acquisition.

To analyze the distributed detection systems in complicated application environments theoretically and overcome the disadvantages, where a high-general and abstract model is lacking for the analysis, guidance and visualized description, a distributed network architecture model from the design point of view of the top level of the system was proposed. We define and analyze our model based on the theory of network calculus. Quantitative description formulas are derived, and the performance analysis method of distributed detection systems based on our distributed network architecture models is established. As validated by the real project, our method is effective and efficient in modeling and analyzing complicated distributed detection systems, which also has been shown general, abstract, guidable for quickly realize of the system.