Analysis And Research On The Operation Of Distribution Network Dispatching Loop Closing

With the rapid development of social economy,users have higher and higher requirements for power consumption.In addition to power quality,they also have higher requirements for power supply continuity,especially for some high-risk customers and sensitive customers.China's distribution network is basically open-loop operation mode,that is,under normal operation mode,the distribution line is single power supply mode,and under fault or maintenance mode,the load needs to be transferred to other lines for power supply through distribution network load transfer mode.The traditional distribution network uses the power cut to transfer the line load to other lines,but the operation mode can not meet the requirements of users for continuous power supply without power cut.With the gradual increase of distribution network equipment,the transformation of distribution equipment is gradually promoted,and the maintenance work of distribution network is also gradually increased.In order to provide users with high-quality,efficient and economic power supply,the distribution network has been transformed year by year,and gradually formed a ring network structure,that is,a 10kV line has two or more power points,which are disconnected at the line contact point.The distribution network has the condition of closing the loop on the primary equipment.At present,according to the requirements of continuous power supply of users,most of the distribution lines with the conditions are closed loop operation,but because there is no corresponding closed loop operation principle,the dispatcher only judges the closed loop operation conditions according to the operation experience,which has certain safety risks;in partial cases,in order to avoid failure,the power cut mode is adopted for load transfer.The main risk in closing operation is that the voltage difference on both sides of the closing point will generate circulating current and impact current in the closing process.When these two currents are superimposed on the load current,it will cause the system power flow change,resulting in the current increase,the protection action trip,and the impact on the normal user power supply.Therefore,if the steady-state current and instantaneous impulse current of the loop closing can be determined in advance,the line fault caused by overload can be effectively reduced,which has an important guiding significance for the loop closing operation.