A framework for evaluating contributions of Inverter Based Resources to grid performance

The drive towards fully decarbonized power systems leads to the widespread replacement of synchronous generators (SG) by Inverter Based Resources (IBR) which should replace not just the energy, but also the services SGs supplied to the system. Inverters interfacing renewables to grids have considerable control flexibility but also certain limitations compared to SG that arise from the nature of power electronics and the resource. Different inverter control configurations can bring distinct system benefits and supply services in new ways. The framework proposed in this paper seeks to join the two sides of the debate on services in future power systems - what can inverters do and what does the system need - and thereby ease the uptake of inverters with grid-supporting capabilities. An evaluation procedure is proposed to quantify the value an inverter installation adds to the system by providing a range of services. A metrics set is defined across three categories, namely, Inverter Metrics, IBR Features and Network Metrics. Inverter Metrics, which are influenced by IBR Features, quantify the inverter’s services provision capacity. These are weighted based on the locational system’s needs for each service as judged by the Network Metrics. The all-round value an inverter adds to the system is calculated from a weighted sum of each service score and indicates not only the inverter’s capacity to provide services but also the importance of their provision for the system. It is intended that this framework could form the basis of an incentives scheme for services provision by IBR.