Study On Increasing The Success Of Fault Reclosure On Sychronization Line Between Distributed Network And Large Power System

Current electricity production, transmission and distribution was mainly on central power generation, long-distance transmission and interconnected power system. This greater capacity of the network has its advantages, but with the increasing peak valley load difference, load rate in power system is a downward trend. And a large power system accident rate, easily leads to widespread power outages. And distributed generation meet the needs of special occasions, make the comprehensive use of energy possible. Therefore, the study of distributed network has important theoretical significance and application value.As many distributed network without effective power regulation, an independent non-plan island comes out after the single tie-line trips off for its fault between the grid and big power. The power imbalance in island system is likely due to abnormal frequency and dramatic voltage changing, resulting in reclosure failure of island, which causes unnecessary power outages. This article has startted a series of studies based on this issue.In this paper, the concept and the characteristics of DG is introduced including some concerned technologies.The principle of autoreclosure and present research are described including optimal reclosure angle, strategies of separation phase closure and adaptive autoreclosure. Drecting to the characteristics of distributed network including weak structure, no quick signal path, long time for the main protection action and etc, establishes the mathematical model and gives the concept of maximum reclosure frequency and closure time. A detailed analysis of the calculation method is proposed. The transient stability trajectory sensitivity is used in control strategies on machine cutting, which determines the order and minimum cutting capacity. introduces generator over-speed cutting compatible with the re-closing time, which can improve the performance of autoreclosure device on tie-line between small grid and great power. The actual system simulation show that the proposed programs and measures can greatly increase the success of the autorelosure for small grid, for a wide range of distributed power with a universal engineering significance.