Graph theory-based feeder automation logic for low-end controller application

This paper presents a graph theory-based feeder automation logic that is applicable to the low-end feeder automation controller, including programmable logic controllers (PLCs) and intelligent electronic devices (IEDs). IEC 61131-3 standard PLC programming languages are used to implement the entire logic engine in SoftPLC programming environment. This logic engine can provide following functions required by the real-time feeder automation application: (1) a dynamic update of the system configuration and the load profile and (2) a generic logic for fault location detection, fault isolation, and power restoration after the occurrence of a permanent fault in the distribution network. The logic engine implemented using PLC languages enables the low-end controller to perform complex feeder automation functions and facilitates end users (usually field electrical engineers) to easily understand and customize the logic. In addition, the SoftPLC technique makes the logic engine development independent of any proprietary PLC or IED hardware. The proposed feeder automation logic is demonstrated by example distribution feeder systems.