Study On Connection Modes Of Distribution Network With Micro-Grid

In recent years, micro-grid is developing very fast all over the world, since it could improve power supply reliability and quality by introducing distributed generation, thus some current serious problems in power grid could been solved. Moreover, affects in connection modes of distribution network emerge simultaneously, mainly including the transmission line's optimal section number, as well as reliability and economy and so on.Based on the profound knowledge of micro-gird structure, operation modes, control technology, the paper summaries effects micro-grid has in power quality, reliability, economy and stability of distribution network. After describing typical connection modes of distribution network and their features, new modes form by adding micro-grid, and relative indices are calculated to compare them in reliability and economy. Specifically, reliability evaluation is made in Single radial connection, Single ring connection, Three segment and three contact connection , and other typical connection modes,while corresponding reliability index models are built, considering System Average Interruption Duration Index(SAIDI), Average Service Availability Index(ASAI) and System Average Interruption Frequency Index (SAIFI). What's more, according to different connection location and capacity, the changing trends of reliability in network is analyzed and suggestions are given about micro-grids'location and capacity. Then in economy analysis, substations, power lines and micro-grid are modeled in economy evaluation, as well as reliability benefits with micro-gird are considered. Similarly, the paper calculates economy trends under different substation capacity and load density. Finally,Based on the reliability model, this paper discusses different connection modes'optimal section number determination method, and then optimal section number of typical connection modes were calculated.