The Research Of Distribution Networks Reliability Evaluation Algorithm

The process of the electricity market making the increasingly high demand for qualityand reliability of power supply. To improve the direct end-user-oriented distribution network’power supply reliability and provide a more secure and reliable, high-quality electricity is thecontinuing pursuit of the power supply enterprise’ goal. Meanwhile, the pattern of powergeneration becomes more diverse affected by the energy and environmental crisis. By theadvantages of flexiblely power generation and environment-friendly, the distributedgeneration (Distributed Generation, DG) technology using the new energy has been attractedunprecedented attention,and become one of the important measures of protect theenvironment, energy conservation, sustainable development for countries around the world.The growing number of DG start to be incorporated into the medium and low voltagedistribution network, leading the structure and operation of the existing distribution networkare significant changed. The reliability evaluation model and methods are correspondingchanged, which makes research DG’ impacts on reliability of distribution network have verygreat significance. The papers main work is as follows：(1) A new reliability assessment algorithm based on reachability analysis and connectionnumber is proposed to disrtibution networks.After learn and absorb a variety of traditional parsing algorithm，a new partitioningmethod conducive to programming is proposed. This method has been combined with thereachability analysis to reduce network traversal when determine failure type of consequences.The connection number is introduced to deal with a variety of component reliabilityparameters’ uncertainty factors.Finally, a new reliability evaluation algorithm is formated bythe combination of partitioning method, reachability analysis, and contact number.(2) The impact of DG operation mode and its access on traditional distribution network isanalysised.(3) The time sequence model of wind generation power output has been established bythe Weibull distribution and auto-regressive moving average model; The time sequence modelof photovoltaic generation power output has been established on the base of solar radiationmodel and environment temperature model; The energy storage device time sequence modelof charge and discharge power under network and island operation; Considering differenttypes of components affected by the weather and their own aging, the component lifecycletime-varying failure rate model has been established.(4) A new reliability assessment algorithm is proposed to disrtibution networks includeDG.while the existing parsing algorithm can not be a good solution to the DG’s impact ondistribution network, In accordance with the of Islanding principle,a new time sequenceMonte Carlo simulation contains a variety of timing proces are used in the example of theimproved IEEE test system RBTS bus6F4main feeder distribution system on reliabilityevaluation.