The Reliability Evaluation Of The Distribution System Based On Feeder Elements And Microgrid Containing Wind And Photovoltaics And Battery

Power distribution system is the fatal connection between bulk power system and its users. In many conditions, this connection is essentially radial. So the power distribution system can easily lead to multi-user outage in a massive area because of a single fault event. The fundamental goal of power supply companies is provide users with economical and reliable power. Reliability analysis of traditional distribution network is mostly based on FMEA to assess. But under the condition of modern interconnected bulk power system, the assessment speed of FMEA is slow and inefficient. Most existing reliability assessment hasn't effectively combined the system and load reliability with its economic benefit.So it is quite necessary to research how to assess the combined power distribution system in a fast and reliable way. After entering the 21 st century, the development and utilization of new energy have aroused man's high attention, influenced by energy and environmental crisis. In recent years, with the rapid development of modern power technology, micro-grid technology based on distributed generation is widely used in modern power distribution system. Because of the accession of micro-grid, the system's structure and power supply methods have changed. So it is quite an important practical engineering significance to research the impact on the reliability to the system and the related users after the combination of distribution system and micro-grid. This dissertation mainly deals with the following work:(1).Provided a reliability evaluation method containing DG distribution system, based on feeder element considering load classification.To cut and divide distribution network through the provided feeder element concept, to realize fast and reliable system assessment after considering main feeder load transfer questions. To optimize DG deploy and enhance partly important load's power supply and system's reliability, by means of results considering load power supply needs and economic benefits.To assess reliability through typical calculating examples.(2).Established various reliability models in micro-grid.Established wind/photovoltaics micro power timing output models,according to randomness features of wind and photovoltaics energy. Established energy storage system charge-discharge models within the micro-grid.Established two-status models of electrical component within the system.(3).Research on the reliability of complementary wind- Photovoltaics combined storage micro-grid which has been connected to the system.To analysis the reliability of the switch and impact of the two micro-grid operation modes,basing on classified feeder elements according to the fault component. On the off-grid mode, provided a load shedding strategy in different regions,according to different needs of load power supply reliability and the connection between micro power and load's relative location. The dessert has also drawn up a output scheme of wind- photovoltaics micro power and energy storage system, under the condition of complementary wind-photovoltaics combined storage within micro-grid, which has been connected to the system. And also has proposed two reliable indexes relating to micro-grid, aimed at regional power supply reliability from micro-grid and power failure loss assessment rate upgrade indexes.(4).Proposed a distribution system reliability algorithm, basing on wind/ photovoltaics/energy stored system which combined with micro-grid, by sequential Monte Carlo simulation.To analysis the impact on changes in micro-grid operation mode, influenced by main grid and micro-grid feeder elements' elemental fault. To establish wind/photovoltaics combined storage power supply scheme and easing load strategy, considering wind-photovoltaics power's random intermittent, load importance and location in micro-grid. To comprehensively analysis the impact on system reliability after such micro-grid have been connected to the system. Proposed a distribution system reliability analysis method, basing on wind-photovoltaics power and energy storage system which combined within micro-grid, by sequential Monte Carlo simulation at last.To verify the proposed methods with the help of the IEEE RBTS BUS6.