Research On Intelligent Control Terminal Of Active Distribution Network Self-healing System

Active distribution power network overcomes the weakness of conventional distribution power network passive control.It has perfect observability and controllability for distributed generation,flexible network topology and other characteristics.At the same time,it can carry on the coordinated control to the DG which connected to the network and realize the function of active planning,active control,active management and active service.Self-healing control is an important technology of active distribution power network,which is based on distribution automation.It is composed of three parts: Main and sub-station,terminal equipment and communication network.Firstly,based on the intelligent distributed FA technology,FTU and distribution automation terminal are improved,then an intelligent control terminal for active distribution power network self-healing system is designed.The terminal is installed on the circuit breaker,the sectional switch and the contact switch on the feeder.According to Multi-Agent control technology,it can collect real-time distribution network operation data,online monitoring of the distribution power network,fault analysis and processing according to the data of the terminal collects and the opposite terminal transmits.Secondly,the protection control module of the intelligent control terminal is deeply studied.Because of the existence of high permeability DG,the conventional10 kV transmission line relay protection mode is no longer applicable,so the longitudinal current differential protection is used as the main protection control mode of the 10 kV transmission line.Aiming at the defects of the longitudinal differential protection affected by the transition resistance,an improved longitudinal differential protection method based on the adjustment factor is proposed,which can effectively guarantee the sensitivity and reliability of the protection.In order to solve the influence of the network topology,the capacity of DG and the load on the setting value of differential protection,this paper puts forward a new method based on cluster analysis and exhaustive method.The setting value of differential protection of the10 kV transmission line can be adjusted according to the change of the three factors.Thirdly,the fault processing module of the intelligent control terminal is deeply studied.The phase selection method based on the phase change of the impedance is used to realize the fault phase selection of the 10 kV transmission line section,which can effectively solve the influence of the power quality,and is more suitable for the active distribution power network system.The fault location of the 10 kV transmission line section is realized by using the double terminal ranging method.In order to improve the ranging accuracy,this method is improved by using the differential full-wave Fourier algorithm with FIR filterFinally,the model is built in Matlab/Simulink to validate the above theory and method.