Electricity System strength, traditionally provided by large rotating machines such as thermal and hydro generation units, helps the grid remain stable following a fault. With the pace of change in Australia’s National Electricity Market, particularly the increasing penetration of asynchronous inverter connected generation – predominantly wind and solar – and retirements of large synchronous plant, concerns over reductions in system strength have been intensifying.
Under the National Electricity Rules, transmission utilities are required to maintain minimum levels of system strength. From 1 July 2018, new System Strength Impact Assessment Guidelines are in effect. These Guidelines reflect obligations on the Australian Energy Market Operator (AEMO), utilities, and (indirectly) market participants, to ensure that changes to the grid do not result in unacceptable reductions in system strength.
PSC has the tools and the people to carry out the suite of analysis required to identify and resolve system strength issues. Our Australian and global teams of PSCAD-fluent system studies experts are well placed to carry out the Preliminary and Full Assessment processes set out in the Guidelines. Whilst the Preliminary Assessment is a relatively straightforward process based around short-circuit ratio metrics, the Full Assessment requires electromagnetic transient simulation (typically using the PSCAD/EMTDC software package) to carry out a detailed analysis of the ability of proposed plant to operate under fault conditions.
PSC’s experience at the intersection of the regulatory environment, technical capability, and the appropriate software tools means we are well placed to provide support and advice to utilities, generators, and system operators, in navigating the changing requirements.