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Aiming at the issue of the supply-demand matching of manufacturing resources in cloud manufacturing, an ontology-based resource storage model and resource matching algorithm are proposed. Firstly, the manufacturing information storage architecture combining relational database and non-relational database is presented to improve the query efficiency of resources. Next, according to the knowledge abstraction method of manufacturing resources, the cloud manufacturing ontology model is established, and the knowledge base is enriched by OWL and SWRL reasoning. Then, combining with the framework of cloud manufacturing resource supply-demand matching and the ontology model of manufacturing resource, the cloud resource ontology model is presented in the relational database and the non-relational database. In addition, in order to address the problem of poverty query accuracy caused by inconsistency between the customers' service requirement and the resource model in the database, resource mapping matching algorithm based on view and granularity is proposed. Finally, the above mentioned key technologies are used to establish a supply-demand service platform for cloud manufacturing resource, and combined with the processing case verification platform that the resource can be matched efficiently, accurately and automatically in cloud manufacturing.

The core element of Metal zinc oxide arrester is a zinc oxide resistance. By establishing equivalent circuit of zinc oxide resistance and using simulation software of EMTP, this paper simulated leakage current of Metal zinc oxide arrester. And we analyze the impact of arrester ageing on leakage current measurement under the steady state. The simulation results show the measurement should first estimate equivalent impedance value of the arrester, and then select the appropriate resistance to match in order to avoid measurement errors.

The fault of control transformer will directly lead to the damage of power supply in the control system of electromagnetic starter, inverter, soft starter and other equipment, and seriously affect the normal operation of such equipment. Herein, based on the analysis of structure and basic working principle of control transformer, the monitoring system for operating parameters of control transformer is designed by using a digital signal processor (DSP). And the voltage monitoring circuit, current monitoring circuit, 3.3 V and 5 V power supply circuit were detailed designed.

In order to improve the safety and reliability of mine hoisting and conveying system, the torque ripple suppression technique of brushless DC motor based on Buck-Boost is proposed. First, the development and current situation of the mine hoisting and conveying system are introduced. Then detailed analyzing the output characteristics of the working state of topology structure and inductance continuous mode for Buck-Boost DC converter. At last, based on the SIMULINK module of MATLAB software, modelling and simulating for Buck-Boost DC converter technique under the working frequency of 20 kHz. The simulation curve of switch tube gate trigger pulse, inductance voltage, inductance current, switch tube current and diode current can be obtained. The simulation results are basically consistent with the theoretical analysis, which shows the rationality of the designed Buck-Boost DC converter model.

Electronic current transformer (ECT) is a new type of high-voltage instrument transformer. It constitutes more components than that of the traditional one. To locate the fault accurately and rapidly during its performance tests, this paper proposed a fault tracing method based on the failure modes and effects analysis (FMEA). From the measuring results of the ECT under test, together with its failure patterns and the test types, we can easily locate its fault in the FMEA tables, and repair them quickly. The presented method is verified to be useful in the results of the analysis on two practical examples.

Considering to the problem of requiring and consuming a lot of storage units by collecting the real time data in the CNC machines, an improved Swinging Door Trending (SDT) compression algorithm has been proposed to compress the massive data. Its tolerance can be adjusted dynamically according to the trend of the fluctuations of the data. In addition, Multi-models optimization method was used for function fitting. And points which have great impact on the compression accuracy are saved according to the error of fitting. Less machine status date can be stored without losing valid information, and get a better compression results.

As the development of smart grid, the growing member of different systems and massive exchange data on distribution network put forward a higher requirement on information integration. Though some systems imported IEC61968 interface and based on Information Exchange Bus (IEB) preliminary achieved information integration between systems, the information none-synchronize between systems still exists. This paper based on the IEC61968 IEB proposed a loose-coupled integration approach for distribution applications, then constructed an integration of distribution advanced applications. The integrated application providing services for the system on IEB with SOA architecture, which can guarantee the unique data source and achieve information integration between applications, loose-coupled structure can also improve the scalability and flexibility of entire system. The feasibility of integrated application has also been verified through case test.

Doubly Fed Induction Generator (DFIG) is emerging as the most preferred technology on Chinese wind farms. Advantages of DFIG include wide-range speed variability and independent active and reactive control in a cost effective way; the major drawback is its poor dynamic behavior during grid voltage dips. Unlike other published papers that validated low voltage ride through (LVRT) strategies through computer simulations, this paper is the first in China to demonstrate results of real field LVRT tests, thus whether a specified wind turbine satisfies SERC Grid Code or not is justified. The field tests were realized by a voltage emulator connected on the wind turbine low voltage side (690V). Various control strategies such as active/passive crowbar and chopper protections were discussed and verified later in this paper.

Wind turbine power performance is an important process of type approval testing project. Because the period of power performance testing is long and it is difficult to collect complete data in a short time, the wind turbine power performance test methods based on least squares prediction is proposed. Firstly, this paper introduces the testing process, site calibration, uncertainty assessment and common data analysis methods of wind turbine power performance using the least square prediction to achieve linear regression and polynomial regression based on limited data. Then the comparative analysis results are carried out through full curve and predicted curve in the actual case to prove the effectiveness of this method in power performance prediction.