1 Efficient Graph Algorithms for Logically Displaying Electricity Distribution Network Systems

Electricity Distribution Networks are normally scattered over large geographical areas. Such distribution networks are a complex networked collection of circuits consisting of primary feeders, thousands of substations, hundreds of switching stations and thousands of overhead poles all linked via switches and cables. Unlike other utilities, electricity distribution circuits are static in position but dynamic in power and flow direction. Therefore, to a control engineer, it is not the geographical location of the device which is important but rather the status of the whole circuit or device and where it is feeding from and what it is feeding. A distribution network is normally drawn or digitized using a graphics package. Systems to process the required network operations are programmed to carry out many of the control centre operations such as adding new stations, retiring old stations, tracing the flow of a given circuit, isolating a station for maintenance, isolating a complete circuit for maintenance, redirecting the flow of electricity, Speed of display of these schematic diagrams and the speed by which the system responds to the commands to carry out the switching operations and then redrawing the circuits correctly and showing the correct status of switches and circuits is of vital importance. Schematically drawn networks coupled with a relational database can be very slow to respond to the emergency switching requirements. This paper presents a logical display approach to process distribution network operations based on the concept of graphs. The graph based approach is distinguished by not having to redraw the circuits after each switchin