Abstract
Abstract Reducing the impact of Geomagnetically induced currents (GICs) on electrical power networks is an essential step to protect network assets and maintain reliable power transmission during and after storm events. In this study, multiple mitigation strategies are tested during worst‐case extreme storm scenarios in order to investigate their effectiveness for the New Zealand transmission network. By working directly with our industry partners, Transpower New Zealand Ltd, a mitigation strategy in the form of targeted line disconnections has been developed. This mitigation strategy proved more effective than previous strategies at reducing GIC magnitudes and durations at transformers at most risk to GIC while still maintaining the continuous supply of power throughout New Zealand. Under this mitigation plan, the average 60‐min mean GIC decreased for 27 of the top 30 at‐risk transformers, and the total network GIC was reduced by 16%. This updated mitigation has been adopted as an operational procedure in the New Zealand national control room to manage GIC. In addition, simulations show that the installation of 14 capacitor blocking devices at specific transformers reduces the total GIC sum in the network by an additional 16%. As a result of this study Transpower is considering further mitigation in the form of capacitor blockers. We strongly recommend collaborating with the relevant power network providers to develop effective mitigation strategies that reduce GIC and have a minimal impact on power distribution.
Plain Language Summary The New Zealand electrical power network was modified in multiple ways to reduce the impact of extreme Space Weather events. By working directly with our industry partners, Transpower New Zealand Ltd, a procedure has been developed to reduce unwanted direct current (DC) at transformers while still maintaining the continuous supply of power throughout New Zealand. This has been adopted as an operational procedure in the New Zealand national control room to manage space weather events. In addition, simulations show that installing DC blocking devices at specific transformers further reduces the risk to the network.
Key Points Collaboration with network power industry partners allows for the development of a more effective, realistic mitigation strategy Mitigation can significantly reduce modeled Geomagnetically induced current (GIC) magnitudes and durations experienced at specific transformers of interest Strategic line disconnections and installation of targeted capacitor blockers can reduce total network GIC by 32%