Research About Renewable Energy Generation In China And Research On Hangzhou 10kV Distribution Network Closing Loop Operation

With the development of china economy, the government is confronted with more difficulties than before, as some conventional energy sources like coal become more and more scarce. So it is essential and important to search for some new energy sources for the further development of power generation.Renewable energy, which mostly contains wind energy, solar energy, hydro energy, biological energy, geothermal energy and Ocean energy, has been commended widely for generation. Renewable energy is not only of great serves abundance, but also distributes widely; it has given its promotion of sustainable development for environment, and should optimize the present power generation structure.From 1990s, renewable energy generation has developed rapidly in China for fund invested and policy supported. However, compared to developed countries, there are many shortages in renewable energy generation, such as capacity, generation equipments, policy support, fund and so on. As it is lack of uniform programming, renewable energy generation has not been applied widely.This paper provides an overview of the status of wind power, solar power, ocean power, hydroelectric power and biological power in China in China, and introduces the main progress of their technology and popularization. And then points that there are still some problems which restrain renewable energy generation, for example, the high generation cost, lack of inspiriting policies compared to some developed countries even some developing countries such as Indian , the lag of technology etc. In the end, some suggestions are given for renewable energy generation future development.At last, a summarize is made and some suggestions for further developments are given. With the high requirement of power quality, supply reliability and the development of distribution network, 10kV level distribution network has formed closed-loop structure. It is the necessary to transfer load without supply interruption by making use of the closed-loop structure. Though it has many advantages by transferring load without supply interruption, the closing loop operation of distribution network will generate large loop current and impact current, which would destroy the system equipments and directly affects the system safety.By now, there is few research about closing loop operation of distribution network. And the operator just makes the decision by experience, which results in accidents occurrence.This paper introduces the concepts and patterns of closing loop operation of distribution network, as well as the reasons of generating loop current.A model of Hangzhou (local) distribution network has been set up to analyze closing loop operation, by using of software PSCAD/EMTDC. The simulation model not only simulate the network power flow before closing loop operation well and truly, but also simulate the system status after closing loop operation, which gives the suggestion weather closing loop or not according to the loop current.Meanwhile, some measures are put forward to reduce the loop current according to simulation. It's the better time to close loop while the loads in the loop network are light, as the phase difference is smaller. The difference of voltage mode could be changed by adjusting the tap of transformer to reduce the loop current. Besides, introduced shows it is a good way to restrict the loop current by using reactance. These measures should give reference to the closing loop operation.In the end, a conclusion is made and some further research problems are pointed.