Wide-area protection of distribution networks using directional agents derived from LV polarising voltage signals and HV current measurements

• Main Author: Potts, Stephen
• Format: Dissertation
• Language: English
• Published: University of Manchester 2021
• Subjects: Directional Comparison Protection; Voltage Measurement; Wireless IEC 61850

Motivation for this project is to contribute to developing a more sustainable future for humankind by helping to reduce dependency on the burning of fossil fuels. Largely this is expected to be achieved by harnessing energy from renewable resources and converting and supplying it in the form of electricity. The project considers the impact that this will have on existing electrical transmission and distribution networks, and discusses changes needed to transition electrical supply networks to the smart operation that will be required to accommodate increasing amounts of electrical energy generated from renewable resources such as wind and solar. A proposal, to evolve distribution network protection techniques to adapt them for application to future networks incorporating large amounts of distributed energy resources, is proposed and researched. Specifically, Directional Agents, combining proven measurement techniques with extra information about power system conditions, are proposed as a method of determining directional information about the flow of power flows across networks. A novel approach is introduced, as a low-cost alternative to traditional approaches, for acquiring critical power system signals necessary to compute the directionality of the power flows. Wireless communications are introduced for consideration as a means to inter connect the component parts. The combination is evaluated for suitability to implement selective, cost-effective directional comparison unit protection, for smart, potentially wide-area, distribution networks. A model of a generic electrical distribution network is created and verified to allow the concept to be evaluated. Simulation models of Directional Agents are designed and validated before being applied to the network model to qualify the protection concepts. The effectiveness of using voltage measurements, acquired from LV locations, to polarise HV/MV protection elements accommodated within Directional Agents located elsewhere on the network at conventional relaying points, is studied. The performance of unit protection schemes formed by interconnection of devices with communications channels is explored. The feasibility of realising the schemes using wireless communications is examined. Simulation test results, combined with literature review and feasibility studies, provide encouragement to develop the proposal for commercial application, as well as highlighting areas for further concept evaluation.