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An on-line tap-changing circuit was developed for use with low voltage transformers (10 kV/380 V, or equivalent), in which the tap positions could be set independently for each low voltage feeder. This allows for possible variation in loads and distributed generation between different feeders fed from a given transformer, allowing the line voltages to be kept within limits on all feeders. A combination of computer simulation and practical experiments was used. A model constructed in Excel gave preliminary results, which was used to specify a more detailed model in Matlab ® Simulink. A small-scale 220/380 V distribution network was constructed, with currents limited to 5 A per phase. Finally, a rotary switch was constructed, suitable for currents up to 500 A, which would be required for a full-scale low voltage distribution network. The results showed that the voltage could be kept within limits, even with a large difference in load and distributed generation from one feeder to another.

Comparing structures of the mechanical engineering courses among three top British universities, the characteristics of their structure is analyzed. Based on the features of Chinese mechanical disciplines, enlightenment from Britain will be applied to course project for principle of machinery, with focus on topic selection and guidance, which will be more efficient than before to develop the students' ability and quality. Also the feasibility and development trend of the topic selection are mentioned.