| Along with the energy crisis and environmental pressures being intensifying,the government and the electric corporation have been being paid more attentions to the Distributed Generation(DG)taking advantages of environment-friendly and flexible operation mode,which are gradually embedded into the distribution system directly connected to users.While Distributed Generations(DGs)are connected,the structure and operation mode of the traditional distribution network will change;moreover,its output power is extremely random and fluctuating;in addition,the access positions,modes and operation methods are flexible and diverse.The reliability of the distribution system may be affected at different levels by each connection mode or operation mode.Thus,study on reliability of the distribution system including DGs shall become very important.In view of characteristics of distribution system and DG and effects of DG on the distribution system,further study was carried out to the algorithm for reliability of distribution system with DGs.This study was summarized as follows:1)An algorithm for reliability of distribution system was put forward based on the modified blocking algorithm and the sequential Monte Carlo simulation method;moreover,the block coupling matrix was defined based on blocking to determine the fault influence range;in addition,those advantages such as rapidity of the blocking algorithm,and handling complicated systems and time-sequence of the sequential Monte Carlo simulation method may be effectively integrated.Thus,an algorithm for evaluation of reliability of distribution system may be formed.2)The model for reliability of common component was modified,in which the mean failure rate was applied to calculate the time-varying fault rate including effects of the service life period of equipment;and then the weather influence factor was introduced.A simple valuation method for the weather influence factor was described,which is closer to actual situations;and effects of those time-varying factors such as weather and service life period of equipment on the equipment's failure rate were fully taken into account.3)Based on the modified blocking algorithm and the sequential Monte Carlo simulation method,the time-series model of DG was introduced.The system state duration was taken for performance of sampling simulation so that time sequences of components,loads and the DG may be effectively integrated;and the system and DG may be synchronously sampled;thus,a calculation method which can effectively reflect the influence of DG on the reliability of the distribution system may be formed.4)By taking Feeder F4 of the RBTS BUS6 testing system as an example,comparison and analysis were carried out to our algorithm and other algorithms to verify effectiveness in solving its calculation speed and accuracy.Moreover,comparison and analysis were also carried out to the modified component model and the traditional model.The reliability of distribution system including DGs was calculated in multiple dimensions such as different combinations,positions and capacities and various island-driven strategies to analyze in detail effects of DG on reliability of distribution system. |
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