Trip Curves and Ride-Through Evaluation for Power Electronic Devices in Power System Dynamic Studies

Abstract

Power electronic devices are widely used in power grid associated with loads and renewable energy sources. With increasing penetration levels of these devices, their response characteristics to short-circuit events can have significant impact on power system dynamics. Power electronic devices are sensitive to voltage sags; they could trip off line under severe voltage disturbances. The ride-through capability of these devices determines if they will remain online. In this paper, a generic method is proposed on how to evaluate the ride-through capability of power electronic devices through trip curves. This method is a two-step procedure. Step 1 is to create a trip curve of the device. Step 2 is to conduct a ride-through evaluation based on the created trip curve and a short-circuit study. Creating a trip curve for a particular type of power electronic devices is critical and challenging. Three case studies are demonstrated in this paper on the trip curve creation for variable-frequency drives, dc drives, and solar photovoltaic inverters based on local and international standards, power grid interconnection requirements, and manufacturer specifications. The proposed method can serve as a general guideline for the trip curve creation for power electronic devices.