Island Grid Operations and Restoration in Electricity Distribution Networks Following Large-Scale Natural Hazards

Abstract

This project is aligned to Electricity Distribution Resilience framework and funded by Resilience to Nature’s Challenges. The goal of this project is to make New Zealand’s electricity infrastructure resilient to natural disasters. Recovery in the immediate disaster aftermath is a major component in this activity. Network restoration is complex from both a strategic and technical view point. From a strategic view point, the distribution network utility should be able to optimise their available resources in terms of crews and spares to determine the best repair schedule. In this case, a priority list is determined from the viewpoint of asset criticality. Also, the interdependency between the electricity infrastructure and other critical lifeline infrastructure should be considered in developing a network restoration strategy. From the technical point of view, the network should utilize the available firm generation (assuming grid connection is lost) to either re-energise (blackstart) the network to form an island that is self-sustaining and can last for a few weeks. This is complex in nature as distributed generation connected to utility is normally designed to provide power when the grid is available. Technical analysis should be done to evaluate the capability of available generation to both energise and sustain the island. The approach taken in the ongoing work is first examination of the generator’s black start capability with all available network components after which critical assets required for this activity are mapped and this can feed into the repair priority list. This will then influence the strategic restoration strategy.