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Design a smart meter data acquisition and analysis system to collect and process electrical energy data, report remote data and collect electrical energy. The data collector of the smart meter supports multiple protocols and the collinear communication of the electric meters, and the collinear communication of the electric meters with different protocols, different models and different communication speeds is connected on the same communication line. The data is sent to the data collector through the RS-485 bus, and the data collector collects and processes the data and uploads it to the server through the WAN. The design of the smart meter data acquisition and analysis system effectively improves the scientific validity of electric energy billing.

It is of great significance to study and analyze the measurement performance and sampling inspection methods of smart meters, and to conduct sampling inspection according to the quality status of smart meters, so as to improve the reliability of smart meters. On the basis of qualified rate test and error test of electric energy meters, radar chart and Wilcoxon rank sum test method are adopted to carry out quality inspection comparison of electric energy meters of the same specification from different manufacturers, and sampling statistical test method is studied accordingly. The method described in this paper is suitable for quality analysis and sampling inspection of electric energy meters.

With the development of the power market reform in China, the state chooses to carry out spot market pilot in eight provinces. PV(Photovoltaic) plant need to face real-time fluctuating prices in spot market, making the investment decisions become more complicated. Considering recent PV power plant investment don’t involve electricity market environment, this paper proposes three different trading patterns of PV plants: full-power day-ahead market settlement, signing long-term CFD or selling electricity to grid with fixed electricity. The PV plant revenue model uses dynamic investment payback period, internal rate of return and cost-benefit ratio to analyze the impact of different patterns on investment. Case study shows that in power pool, signing CFDs can effectively reduce the investment recovery period of PV plants and improve investment return.

Electrochemical migration (ECM) of metal has been studied for decades, including Ag, Ni, Sn, Pb, Cu and Au. These metal materials are commonly used in microelectronics devices, both in package and die. According to the failure mechanisms, some of the root causes are easy to find out except Au, since contaminant element is hard to be detected, and electrolyte is various besides water. In a real failure analysis case, we developed a method to analysis contaminant and alcohol induced ECM of Au bond by combining ion chromatography and TOF-SIMS characterization, and IVA analysis. Based on the coupled analysis, the origin of Au ECM is related to chlorine ions and dominant electrolyte formed in low temperature (-45°C) is alcohol. These results indicate alcohol control in microcircuit plays an important role in sealed package.

A general analytical model, formulated in 2-D polar coordinates, is developed to predict the unbalanced magnetic force, which results in permanent-magnet brushless ac and dc machines having a diametrically asymmetric disposition of slots and phase windings. It is shown that the unbalanced magnetic force can be significant in machines having a fractional ratio of slot number to pole number, particularly when the electric loading is high. The developed model is validated by finite-element calculations on 9-slot/8-pole and 3-slot/2-pole machines. In addition, the unbalanced magnetic force has been measured on a prototype 3-slot/2-pole machine and shown to be in excellent agreement with predicted results.