Approach To Setting For Intelligent Switches Based Feeder Automation And Realization Of Setting Software

To facilitate the application of feeder automation(FA) based on Recloser and Voltage-Time Type of Sectionalizers, approachs of the parameter setting are investigated. A hierarchical model of distribution network is proposed, in which electrical source node is regarded as the root of a tree, twig node and interconnection switch are regarded as the terminals of a tree. Under the condition that at any moment during the procedure of fault detection there is only one sectionalizer being switched on, the setting method for X–time limit of sectionalizer and that for XL–time limit of interconnection switch in looped distribution network are expounded. As the setting principle of interconnection switches in basic multi–section multi-interconnected distribution network that all interconnection switches possess same XL–time limit, the setting method for the XL–time limits of interconnection switches in expanded multi–section multi–interconnected distribution network is also researched. The case study result of each given setting method shows that these methods are feasible.Improvements were made to solve the problems of Basic Instantaneous Protection based FA, such as long restoration time for temporary faults and expansion of fault influence region due to over load. The source switches are improved to be able to re-close twice. The sectionalizers are tripped with delay when out-of-voltage. An out-of-voltage lock mechanism is also added to sectionalizers. It is pointed out that the X-time values of sectionalizers can be set to a same value. A hierarchy model of distribution network is proposed,on the base of which, the principles to set XL-time of looped switches are described. A linear planning approach is proposed for setting the XL-time values of looped switches. Practical examples are given to show the feasibility of the proposed methods.In order to record each operation, an edge-edit-table and a node-edit-table are introduced. Not only is the undo operation achievable,but also the dynamic modelling is reached. Improvements have been made for the traditional net-base adjacent table, a simplified model of distribution system is modified by a net-base adjacent table with N lines and six columns. A fast incremental approach to distribution network modelling is put forward.Based on above works, an application software based on VC++6.0 is developed, which can obtain the setting values for both recloser and sectionalizers based FA and instantaneous protection based FA. A convenient man-machine interface with graphic based modelling technique is reached. Testing results on some examples show the software is feasible.