An effective power system protection scheme has to be able to detect and locate all occurring faults corresponding to low and high impedance values. The latter category poses the greatest challenge for the protection schemes due to the low values of the related fault current. This paper extends previous work by the authors on the subject, aiming to achieve detection and location of high impedance faults (HIFs) in multiconductor overhead distribution networks utilizing power line communication (PLC) devices. Fault detection is proposed to be performed by a PLC device installed at the starting point of the monitored line and by using differences to the values of metrics related to input impedance at frequencies utilized by narrowband systems. Moreover, fault location can be derived by a response to impulse injection procedure utilized by all installed PLC devices along the line. The method is evaluated and validated in various simulation test cases concerning its ability to effectively detect and locate HIFs.

This paper introduces the idea of unified unit commitment and economic dispatch modeling within a unique tool that performs economic dispatch with up to 24-hour look-ahead capability. The tool provides financially binding dispatch and ex-ante locational marginal prices (LMPs) for the next 5-min interval and advisory commitment, dispatch schedule and prices for the remaining scheduling horizon. Variable time resolution and variable modeling complexity are used in order to reduce computational requirements. A finer time resolution and detailed modeling are used during the first hours of the scheduling horizon while coarser time resolution and simplified modeling during the last ones. The viability of the method for medium-sized systems is demonstrated through its application to the Greek power system.

No abstract

Abstract-Power distribution network protection and restoration are significant issues in terms of quality and reliability of the supplied electrical energy. In this paper, an extended research in possible high-end protection and control methods is presented. The authors intend to show the efficiency of combining modern IT techniques with the equipment provided by distribution automation evolving technology. As a result, a flexible and versatile multiagent system (MAS) is proposed. The effected MAS is fault isolation and power restoration oriented, as shown in the case studies. The structure of the proposed system (software and hardware aspects) is introduced. Both microscopic and macroscopic procedures are revised. Power line communications technology is implemented. Results acquired from computer simulations are evaluated. Conclusions concerning the perspectives of implementing the proposed system are finally presented.

No abstract