This page is listing and linking large disturbance events around the world where initial disturbance event resulted in unexpected tripping or significant active power reduction from Inverter-Based Resources (IBRs). The list is not necessarily exhaustive, please let us know (by emailing julia@esig.energy ) if you are aware of other large events that should be linked on this page.
North America
The Electric Reliability Organization (ERO) Enterprise, comprised of North American Reliability Corporation (NERC) and six Regional Reliability entities, have implemented an Event Analysis Process to promote a structured and consistent approach to performing event analyses in North America. The event analysis process serves as a learning opportunity for the industry by providing insight and guidance by identifying and disseminating valuable lessons learned from large disturbance events. The ERO Event Analysis Process document available here describes categories of events that are subject to the ERO Event Analysis and a process of event analysis itself.
The bar chart below focuses a subset of disturbance events from ERO Event Analysis Process, where a normally cleared fault resulted in unexpected large MW loss due to tripping or active power reduction of IBRs. For each event the bar chart illustrates the amount and type of unexpected generation loss.
Major Event Reports
April 2023 Southwest Utah Disturbance Report
March/April 2022 California Battery Energy Storage System Disturbances
June 2022 Odessa Disturbance Report
March 2022 Panhandle Wind Disturbance Report
June-August 2021 CAISO Solar PV Disturbance Report
May/June 2021 Odessa Disturbance Report
July 2020 San Fernando Solar PV Reduction Disturbance Report
April and May 2018 Fault Induced Solar Photovoltaic Resource Interruption Disturbances Report
October 2017 Canyon 2 Fire Disturbance Report
August 2016 1200 MW Fault Induced Solar Photovoltaic Resources Interruption Disturbance Report
August 2003 Northeast Blackout Event
Great Britain
The power disruption on August 9, 2019, in Great Britain was primarily caused by a lightning strike on a transmission circuit (cleared in under 0.1 s), triggering unexpected reductions in generation. Initial losses included the expected loss of 150MW from distributed generation due to the strike. However, the more significant impact came from Hornsea offshore windfarm reducing supply by 737MW and Little Barford power station’s steam turbine tripping, resulting in a loss of 244MW. This generation loss resulted in rapid fall in frequency and further loss of distributed generation, bringing a total generation loss to 1,691MW, exceeding the system’s “backup” capacity at that time (dimensioned to cater for the loss of the largest infeed at 1,000MW). This critical loss caused a rapid decline in frequency, necessitating the activation of the Low Frequency Demand Disconnection (LFDD) scheme, which automatically disconnected approximately 1GW of demand to stabilize the network (Note that following the LFDD schemes being triggered, the second gas turbine at Little. This resulted in approximately 1.1m customers being without power for a period between 15 and 45 minutes. Full report of the event can be found here.
Australia
On Wednesday September 28, 2016, severe tornadoes in South Australia caused significant damage to key transmission lines, leading to multiple faults in quick succession on the grid. The tripping of these lines caused multiple consecutive voltage dips, triggering protective measures in nine wind farms which reduced their power output by 456 MW in under seven seconds. This sudden reduction in generation increased the load on the Heywood Interconnector between Victoria and South Australia, leading to its automatic disconnection that isolated South Australia’s power system from the rest of the National Electricity Market. With insufficient local generation to meet demand, the islanded system’s frequency collapsed, resulting in a widespread blackout. AEMO’s analysis concluded that following the system separation, the frequency collapse and subsequent blackout were unavoidable due to the imbalance between generation and demand. Full report of the event can be found here.