Research On Rapid Fault Diagnosis And Management In Intelligent Distribution Network

As the last segment of power generation and supply,distribution network is directly connected to the users,and affects the security and reliability of power supply.With the rapid development of national economy and the improvement of people’s living standard,the quality of power supply is also increasing.The demand of rapid fault diagnosis,isolation and power supply restoration in small-scale with less manual intervention is more and more urgent.Fault characteristics of single-phase grounding in neutral grounding via arc suppression coil system was analyzed in this thesis.Theories of fault identifecation and location based on steady components were studied and compared,and success rate of fault line detection with neutral grounded system by arc suppression coil with parallel medium resistance was found increased.Based on the analysis of the current status of the arc suppression coil in Hangzhou,two optimization and reconstruction schemes for the problems of the arc suppression coil were put forward.Phase-frequency characteristic of transient zero-sequence current of single-phase grounding in neutral grounding via arc suppression coil system was discussed.Fault line detection device based on the phase-frequency characteristic of transient zero-sequence current in feature band was designed and trial operated in a substation.The principle and design were conformed to requirements of rapid fault location of the single-phase grounding line.The demand of primary grid structure,main station system,sub station system and distribution terminal for the construction of diatribution automation was also discussed.The principle of fault diagnosis and location in distribution network was studied,and the corresponding algorithm was given based on the distribution automation system.Cooperation schemes of relay protection and distribution automation to isolate fault section were put forward according to overhead lines and cable lines.The feasibility of fault diagnosis,location and isolation in distribution network was demonstrated under the framework of distribution automation in Hangzhou.A fast distributing load recovery scheme under 10 kV bus fault was proposed and realized in the distribution automation system of Hangzhou.With this scheme,the power supply could be fast and effectively restored under the case of large-scale power failure.