Aggregation of Power Response Matrices for System-Level Analysis in Converter Dominated Power Systems

Abstract

With the increasing integration of renewable energy, power systems have become more complex due to the widespread use of power electronic converters (PECs) and their diverse control strategies (e.g., grid-following, grid-forming). The impedance-based approach in small-signal analysis of the system has been widely used, since it can be applied to blackbox system measurements in the frequency domain. However, dq-domain impedance (most commonly used for AC systems) representations are abstract and less intuitive for power engineers. To address this, the power response matrix (PRM) has recently been proposed as an alternative framework. This paper aims to extend the PRM framework by exploring the methods for aggregating individual subsystems' PRMs to form an equivalent PRM. Two approaches are examined: (1) deriving an equivalent impedance and subsequently converting it to a PRM, and (2) directly aggregating the subsystem PRMs. The proposed aggregation methods are compared and tested in an example scenario consisting of an offshore wind farm. Both methods are shown to yield identical results.