A Novel Voltage Based Approach to Self Powering the Next Generation of Smart, Compact and Communicable Auto-Reclosers for Distribution Networks

During the past decade a number of pole top reclosing devices have entered the market to improve the reliability of lateral lines. These devices have been characterized by the fact they are self powered from the line they protect and have the electronic controller integrated with the vacuum interrupter floating at line potential. The enabling feature and ultimate limitation of these first generation devices is the use of the current in the primary circuit as the source of power. A product self powered from line current has two fundamental deficiencies. The first is that the entire operation of the device is dependent upon a minimum line current being available to provide any power to the controller. The second is that the fault and load current ratings of the switch are restricted by the complexities imposed on the primary current path to achieve the self powering. This paper presents a new compact and cost effective voltage based method of providing power to intelligent pole top devices. The approach uses an R-C chain of electronic components arranged in a novel manner that is capable of withstanding impulse and power frequency voltages whilst providing a reliable power supply suitable for micro-controller electronics and short range communications. This method decouples the power supply from the fault and load current ratings of a switching device enabling a much greater field of application.