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In recent years, global energy and environmental problems have become increasingly prominent, and wind power has entered a period of rapid development. At the same time, offshore wind power integration is also facing many challenges and problems. Based on the analysis and research of offshore wind power integration, this paper introduces the technologies of offshore wind power integration such as HVAC, LCC-HVDC and VSC-HVDC, and discusses the impact of large-scale offshore wind power on power grid, interaction with UHVDC, voltage ride through and harmonic vibration of offshore wind power, and the impact of large-scale wind power integration on power grid and power quality problems are studied. The research and breakthrough of these problems will greatly benefit the development of offshore wind power industry.

In view of the fact that the AC system with multiple LCC-HVDC feeds is prone to simultaneous commutation failure, this paper proposes the scheme of grid division for the multiple feed system to isolate the coupling between multiple HVDC and reduce the risk of occurring simultaneous commutation failure. First, N-1 scan is performed on the multi-feed system to find the set of lines that can cause simultaneous commutation failure of multiple HVDC. The line with high line load rate is removed from the line set. Then, on the basis of local expansion theory, the nodes in the system are aggregated to form the initial partition. In this process, the calculation method of voltage/reactive sensitivity matrix considering PV node and LCC-HVDC is firstly given; moreover, the corresponding indexes were calculated by the node aggregation function and the partition fitness function. Finally, the results of the partition are modified by considering the circuit set and the partition short circuit ratio, and the flow chart of the partition scheme is given. The partitioning process is validated with an IEEE 39-node system as an example. The results show that the partitioning method is reasonable and solves the problem of the failure of commutation effectively.

In order to study the influence of test condition on rheological property of asphalt combined binder, the paper uses five kinds of filler-bitumen ratio and different temperature condition.by the rheological test, it studies the asphalt combined binder on n the high-low temperature and fatigue performance. The result indicates that mineral powder can strength the high temperature performance, but it is bad for low temperature performance and fatigue performance; when test temperature is more higher, it’s high temperature performance and fatigue performance weaker, but it’s low temperature performance strength; co nsidering the high-low temperature and fatigue performance, it suggests the reasonable filler-bitumen ratio range is 0.8-1.0.

Doubly fed induction generator (DFIG) has become the most widely used type of wind power generation due to its superior technical performance. Series compensation technology is widely used in large-scale and long-distance wind power transmission system because of its high cost performance and significant improvement of transmission capacity. However, it may cause subsynchronous oscillation (SSO). This paper first introduces the definition and harm of subsynchronous oscillation, and then analyzes the advantages and disadvantages of series compensation technology, as well as the mechanism and suppression measures of subsynchronous oscillation of DFIG connected system through series compensation. Through modeling and simulation analysis, the suppression effect of additional subsynchronous damping controller (SSDC) on subsynchronous oscillation of DFIG control system is verified.

The analysis of railway passengers’ travel choice behavior plays an import role in railway passenger product design and transport organization. Many researchers focued on it and lots of models and methods had been proposed. With the rapid development of information technology in recent years, deep learning models are more and more widely used in many research fields, and also applied in this research. Based on the OD train ticket data of Beijing-Shanghai high-speed railway line, it studied travel choice behavior of passengers in Beijing-Shanghai high-speed railway line during the weekday, and then took attributes of ticket data (arrive-departure station, arrival-departure time, etc.) as the mapping features to study passengers’ choice of different trains, The result shows that the method given by the research has quite high fitting accuracy.

The performance of the circuit breaker mainly includes mechanical performance and arc extinguishing performance. This paper reviews the current status of its detection methods. Research indicates that the dynamic characteristic instrument method can meet the needs of offline detection for the detection of mechanical properties, but it cannot be implemented with electricity. The traditional method for detecting the degree of contact ablation is the electrical life method, which determines the change in the degree of contact ablation of the high-voltage reactive switching switch by the weighted calculation of the number of breaking and the breaking current. This method can only reflect the deterioration of the contact ablation degree of the high-voltage reactive switching switch, but it cannot reflect the abrupt or abnormal contact ablation degree deterioration. It is necessary to carry out research on new technology for live detection of circuit breaker performance.

Large-scale periodic gold network electrodes were fabricated using the developed and versatile nanosphere lithography technique. The fabrication processes, structural characterizations and network formation mechanism were described in detail. An enhanced optical transmission peak was observed from the transmission spectrum, which could be assigned to the extraordinary transmission mediated commonly by (a) localized surface plasmon resonance (LSPR) and (b) surface plasmon polaritons. The effects of film thickness, sphere diameter (periodicity) and reactive ion etching time on their optical and electrical properties were also investigated. By controlling these three independent variables, we could tune the SPR peak position and their light transmission distributions flexibly. Our large-scale continuous gold network can serve as a transparent conductive electrode, while possessing the role of a surface plasmonic resonance component can make it very attractive for potential photo-electric device applications in a range from plasmon-enhanced broadband photovoltaics to SPR-based chemo- and biosensors.

The dynamic photo induced charge separation and transport properties of pulsed-magnetron-sputtered TiO2, WO3, and WO3–TiO2 double-layer films were investigated using the transient photovoltage (TPV) technique. Effective charge separation and transport were observed for the WO3–TiO2 heterojunction, which was about three times larger than those of the TiO2 and WO3 single-layer films. The TPV response of the WO3–TiO2 heterojunction peaked at 28 ns with a recombination lifetime of 179 ns. These results suggested that the electron injection from TiO2 under illumination was the dominant factor for the separation of photo induced charge carriers in the WO3–TiO2 double-layer films.

Vertical aligned ZnO nanorod (diameter = 50 nm) arrays on indium tin oxide (ITO) substrates have been grown using a new two-step soft chemical procedure. The resulting current-voltage (I-V) characteristics of the ZnO nanorods exhibited a clear rectifying behaviour. This rectifying behaviour was attributed to the formation of a Schottky contact between the Au coated atomic force microscopy (AFM) tip and ZnO nanorod (nano-M/SC) which was dominated by the surface states in ZnO itself. Photo-assisted conductive AFM (PC-AFM) was used to demonstrate how the I-V characteristics are influenced by the surface states. Our I-V results also showed that the nano-M/SCs had a good photo-electric switching effect at reverse bias.