  The suitability of the QDL method for analyzing the performance of ac power
systems has been evaluated by application to a microgrid. The QDL method is
based on a combination of Quantized State Systems (QSS) methods and the Latency
Insertion Method (LIM). The accuracy and computational intensity of QDL
simulations were evaluated relative to an industry-standard reference method.
The key advantages expected of the QDL approach -- including high computational
efficiency when the system is operating in steady-state and, when not in
steady-state, the need to update only those states that have been affected by
quantum level changes of connected states. The expected advantages were largely
realized, but with some complications that remain unresolved and require
further research such as limit cycle oscillations that emerge in some states
after disturbances that should have returned to stationarity. Also, the method
in its current state may not be feasible for fault analysis because of the low
computational efficiency that results when large disturbances (e.g. faults)
create large excursions simultaneously in many system states. The relative
strengths and weaknesses of the method are discussed, and some improvements to
the method are proposed to overcome the weaknesses. The revelation of observed
problems is intended to inspire additional research to overcome those problems.
