Considering the time-sequence characteristic and randomness of load and natural resources, this paper studies on the distributed generation (DG) impacts on voltage limit violation probability of distribution lines. The time-sequence characteristic and randomness of load, wind and photovoltaic (PV) generation are analyzed; the indices and risk levels of voltage limit violation probability of node and distribution line are proposed. By using probabilistic load flow based on semi-invariant method, the impact degrees of voltage limit violation are calculated with different distributed power penetration levels, different seasons, different time periods, different allocation ratio between the wind power and PV power. Voltage limit violation laws of distribution line, which are concluded by IEEE33 bus system simulation, are very helpful to guide the voltage regulation of distribution line including distributed generation.
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