Research On Reliability Issues Of Distribution Power System With DG Integration

As a link of the end user and the generation transmission system, the distribution system is a very important part to ensure safe and reliable power supply for user. With the rapid spread of distributed generation integration of distribution system, with its own characteristics, distributed generation brings a variety of impact to distribution system, of which including the impact of distributed generation integration to distribution system reliability, to distribution system power supply capability, and to distribution system operation reliability. After the distributed generation integration, traditional distribution system reliability evaluation method is no longer applicable, at the same time due to the distributed power output, power supply capability of distribution system would be improved, and with the changing reliability of distribution system, the maintenance strategy of distribution system would also be affected.Therefore, carried out depth study on distributed generation integration distribution system in reliability level, to effectively guide the popularity of distributed generation development, is the priority problem to be addressed at this stage. For this situation, based on the achievement of traditional distribution system reliability evaluation, power supply capability evaluation and reliability operation and maintenance strategy planning, the research of distributed generation integration distribution system in reliability level was carried out:After a thorough analysis of the impact of reliability of distributed generation integration distribution system, the indices and models for reliability evaluation of distributed generation integration distribution system were summarized, preparations were made for expand study of reliability evaluation of distributed generation integration distribution system. Sequential Monte Carlo reliability evaluation model based on feeder segmentation of distributed generation integration distribution system was proposed, the segment coding method and system failures affect classification and seeking logic were built, equipment outage model and equipment output model for Sequential Monte Carlo reliability evaluation model was chosen, load reduction strategies during islanding under balance of distributed generation and load was proposed also, and for discover the match degree of different distributed generation and load types, the match degree assessment method was developed, then the reliability and match degree of distributed generation integration distribution system was analyzed by a case study.Based on the reliability evaluation method of low distributed generation penetration distribution system, the power supply capability analysis for distributed generation integration was carried out, the transfer load dealing ways after distributed generation integration was studied, and the effective load carrying capability was defined, finally the power supply capability analysis method based on reliability was built, and then the effect on load transfer capability by distributed generation integration was analyzed.The traditional distribution system operation and maintenance methods was improved by combining it to distribution system reliability. Through analysis of regional distribution system failure factors, and combining the historical fault statistics data of regional distribution system, the failure factors proportion matrix of distribution system equipment was proposed, by disintegrate distribution system equipment fault rate with failure factors proportion matrix, the correction model for each disintegrated was built, using the correction model to reflect the real fault rate under certain equipment state and certain external environment state, and using the corrected fault rate to calculate reliability influence degree of each equipment type, using the influence degree to guide the maintenance strategy planning work. And under this achievement, the distribution system maintenance strategy planning methods consider distributed generation was proposed, which considered the impact of distributed generation output under certain external environment state, at last,the distribution system equipment reliability risks discrepancy of system with distributed generation and without distributed generation was analyzed.