Modeling of Inverter-Based Resources Using Equivalent Current Sources in EMTP-RV

Abstract

This paper presents a time-domain, equivalent current source model (CSM) for inverter-based resources in EMTPRV for evaluating their harmonic impacts, behavior, and interactions with the grid. Whereas detailed inverter models can be accurate if the inverter design and parameters are precisely known, their simulations are time-consuming. Moreover, the lack of information about topology and control schemes from inverter manufacturers makes these models difficult to hand-tune and leads to loss of accuracy. The CSM proposed in this paper, simple yet reasonably accurate, represents an inverter-based resource along with its step-up transformer as a parallel combination of harmonic current sources. The development and validation of a CSM is presented using a grid-connected detailed inverter model as a basis. CSMs can be used to represent multiple inverter-based resources like solar farms in a network – to study harmonic interactions between them, evaluate their impact on weak grids, and develop mitigation solutions.