Distribution Systems Optimal Power Outage Restoration Enhancement through the Application of State Estimation and Protection Coordination Analysis

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Unlike transmission systems, distribution networks present an unbalanced and unsymmetrical topology that lacks observability and controllability. Being traditionally designed and operated in a radial configuration, any outage event implies the de-energization of downstream customers. Distribution Network Reconfiguration (DNR) is a well-established practice that changes the network configuration by opening and closing switches to optimize one or multiple operational aspects, such as power outage restoration. Due to the need for fast and assertive decisions to minimize costs and prevent cascaded outages, restoration techniques have been automated to avoid operators’ intervention and take action within the first minutes of the event. The recent methodologies for automatic restoration solutions assume the availability, knowledge, and accuracy of node-by-node measurements, which is not a reality in actual distribution systems. Even though the current trend in grid modernization has increased the integration of teleoperated Intelligent Electronic Devices (IEDs), such as relays, reclosers, meters, load sensors, and switches, to improve energy delivery quality, continuity, and reliability, obtaining reliable electrical measurements on every node is still technically and financially infeasible. Based on that, this research proposes enhancing automatic outage restoration solutions by embedding the State Estimation (SE) technique, which can be used to estimate the best fit of the system’s state variables based on the network topology and a reduced number of actual field measurements. The presented methodology is capable of making the network observable through SE to then perform fault location and isolation, protection miscoordination detection and correction, optimal restoration, and restoration switching sequence. Even though compounded by time-consuming features, the solution is designed to present time efficiency while also accounting for Distributed Energy Resources (DER) presence in the network. The methodology is developed and validated by Software-In-the-Loop (SIL) and Hardware-In-the-Loop (HIL) simulations using benchmark distribution networks with different sizes and topologies for validation, comparison, and evidence of its effectiveness.

Embargo status: Restricted until 01/2027. To request the author grant access, click on the PDF link to the left.

Distribution Systems, Power Outages, State Estimation, Optimization, Restoration