| Nowadays, as the demands of power supply reliability and energy quality areincreasingly high, traditional centralized electricity system, with large crew and largepower grids as the main feature, has been unable to meet such demand. On the otherhand, the reform of global electricity market mechanism provides a competitiveplatform for the independent power operators. Based on the technological progress ofelectric power industrial and human attention for their own survival environment,Distributed Generation (DG) technology has become a new hotspot in the field ofpower systems.With the interconnection of Distributed generation (DG), distribution systemdevelops to active loop-network from traditional passive radial-network. Stability andflexibility of electricity supply in distribution system have improved largely, however,several challenges to system operating security and reliability are brought forward inthe mean time. Parameters in distribution system as well as the conditions forover-voltage can be impacted due to Distributed generation. This paper just focuseson this problem.The basic concepts of DG and over-voltage are introduced simply in the paper atfirst. Both of the significance of developing DG and impact on distributed system arediscussed, and the mechanisms of various resonances are analyzed in detail. Then,based on the platform of PSCAD/EMTDC, a small induction generator, synchronousgenerator and its associated controller are designed according to the desire of applyingDG. Several over-voltage problems introduced by the interconnection of DG aregenerally discussed, and a 10 kV Hangzhou distribution system model is establishedto test the proposed theoretic analysis. Simulation results illustrate that the capacity ofvarious DG, load level nearby and parameters in distribution system can impactover-voltage caused by DG definitively. At last, this paper makes a brief discussionon corresponding solutions to restrain over-voltage caused by DG. |
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