Research On Evaluation Of Typical Connection Modes Of Distribution Networks

Since 1990s, with the rapid development of national economy, an endless stream of new residential area and the City Economic Development Zone emerges in endlessly, and city power load growth is accelerated obviously. The increasing consumption of electrical energy demands higher quality and power grid reliability, and especially the low-voltage power grid closer to users is facing greater pressure, so the importance of distribution network can not be ignored.The choice of connection mode has been directly related to the quality of distribution network structure. The research in recent years, reliability, economy, power quality, "N-1" and "N-2" safety criteria are often used. Different connection modes have different characteristics, with unequable scopes of application. When choosing mode of connection various factors should be integrated with the consideration. Therefore, various types of the distribution network connection modes are needed to be summarized. By studying the characteristics of the system, a strong basis for better planning of distribution network connection can be provided.Based on the in-depth study of the status of connection mode of distribution network in China, the characteristics of each kind of connection mode and the effect to distribution network of the combination of different methods are respectively analyzed and studied; reliability index, economic index, safety index of distribution network and evaluation methods of different indicators are studied, Based on analysis of different evaluation methods and indicators, optimized evaluation system and improvement methods are established. Based on the literature analysis, the distribution network security index and the evaluation system of distribution network connection mode have been improved. Elementary connection theory is introduced according to the structure characteristic of connection mode. By using the membership model in the evaluation system of elementary connection, the comprehensive evaluation of different element connections is realized. Power grid planning is very important to development of the power system, however, the plan with a certain blind area is usually considered only from a single regional single aspect of information. By using the load fusion the planning can be structured as a whole, with some defects in design being overcame. By using optimal planning methods a 10kV with wiring way in distribution network by dividing regional stages, the distribution network has been designed and planned, with very good reference value. Through the analysis of examples, it shows the feasibility of the proposed safety index, the dynamic comprehensive evaluation system of elementary, and the proposed method of selecting of electric network connection mode using load fusion.