Power Response and Modelling Aspects of Power Electronic Loads in Case of Voltage Drops

TL;DR

This paper investigates the power response of power electronic loads during voltage drops, develops dynamic models for stability analysis, and compares their impact to constant power loads, showing improved stability contributions.

Contribution

It introduces new dynamic simulation models for power electronic loads under voltage drops, aiding voltage stability studies.

Findings

Models accurately capture load dynamics during voltage drops.

Power electronic loads positively influence short-term voltage stability.

Models outperform constant power load assumptions in stability simulations.

Abstract

In this paper, the power response of power electronic loads in case of voltage drops are measured and their dynamics are analysed. Based on this, dynamic simulation models are derived which can be used for voltage stability investigations. For this, four loads with different power factor techniques are considered. In addition, the impact of the grid impedance and input filter on the power response are measured in the laboratory. Based on the measurements, the simulation models are described. It is also outlined under which aspects the components of the loads are normally dimensioned if no detailed information is available. A comparison with the measurements demonstrates that the simulation models capture the main dynamics. At the end of the paper, the load models are compared to a constant power load in a short-term voltage stability use case. The results indicate that the power electronic loads have a more positive influence on short-term voltage stability in case of voltage drops. Overall, the contributions of the paper are the identification of the basic power dynamics of power electronic loads for different voltage drops and a subsequent derivation of suitable simulation load models for voltage stability investigations.