  This paper presents an investigation into load dynamics that potentially
cause voltage instability or collapse in distribution networks. Through
phasor-based, time domain simulations of a dynamic load (DL) model from the
literature, we show that the load dynamics alone do not cause voltage
instability or collapse. By comparing the DL model to a benchmark model, we
identify an important limitation with the DL model. We characterise this
limitation and recommend that future work use load models with physical state
variables. By investigating when and how load dynamics cause voltage
instability, we are well-positioned to develop systems to control and maintain
voltage stability in distribution networks.
